Monthly Archives: October 2018

Baby giant clams at Civa Fiji

The pearl farmers at Civa on the lovely island of Fiji are about to make a pearl harvest but took a few seconds to allow me to share these photos of the baby giant clams which they are also raising with you all.

Baby giant clams now being raised in Fiji

Baby giant clams now being raised in Fiji

The partnership between Civa (Fiji) Pearls Limited and the Douglas Fam­ily of Matagi Island have given their first al­lotment of giant clams from their hatchery to the Vanua Trust of Laucala.

A project that started in 2016 is now pro­ducing around 25,000 giant clams juveniles every three months destined for the export market.

The hatchery is producing four species of clams (Tridacna Maxima, Tridacna Noae, Tridacna Squamosa and Tridacna Derasa).

giant clams

the baby clams are between 5cm and 8cm

A portion of the production is destined to reef rehabilitation projects and for the de­velopment of the resource through the tra­ditional fishing rights owners.

The hatchery is situated in Qamea Island and the coastal communities of Qamea and Naqelelevu will benefit from this long-term project by receiving yearly allotments of clams for their development.

baby giant clams

The giant clam hatchery. Double redundant fresh water system to ensure the clams are as happy as..well…clams

Civa (Fiji) Pearls Ltd owner Claude Michel Prevost said they are happy to follow up on their promises to deliver to the local coastal communities their share of this commodity.

“We are happy to see this happening. We think that it is important for companies who benefit from the development of this resource to include the traditional custodi­ans in the development of this resource.

“The development of aquaculture is in its infancy with few players. The Ministry of Fisheries is sending signals that it wants to develop aquaculture and this is great news.

giant clam

Aren’t they pretty?

Civa (Fiji) Pearls Limited was founded in 2006 by two Canadian expats Claude Michel Prevost and Danielle Belanger.

Lured by the extraordinary colours al­ready in production in Fiji, Claude and Danielle began their own pearl production in 2007 with a subsequent first harvest in 2010.

Most of this production is currently ex­ported to Europe, with a small amount retained and available from partnering re­sorts here in Fiji.

The pearl farm is situated on the wind­ward side of Taveuni.


Fiji pearls, civa

Civa pearls – fiji pearls are distinctive

Should we try to stock some?


AAA Grading system

Pearls are usually graded between A and AAA, with A being not very good to AAA which should be of the specific shape (usually used for round pearls) smooth surfaced (with only very small and near invisible flaws) and of high shine or lustre

AA+ Nearly as good as AAA but perhaps slightly off round when rolled and a few more flaws although these will still only be visible on close inspection. Look closely below- the halos are slightly oval because the pearls are off-round although the halos are still pretty regular

AA Average to good lustre, off round, blemishing to 20% of surface

A: This is the lowest jewellery-grade pearl, with a lower lustre and/or more than 25% of the surface showing defects. Probably a ’round’ pearl will be egg shaped, even from a distance

The problem with this system is, of course, that you may be faced with a smooth surfaced and metallic pearl which is off round to the point where it drops from AAA to AA+ or even AA. It will still be a beautiful pearl and one which will probably look round when worn but many buyers will be deterred by an AA grading.The lustre reflection below differs noticeably between pearls in terms of reflection and shape and the one to the left of centre has a grooved surface flaw’

A+ Low quality. Visibly off round and very variable lustre. Many flaws in the surface

(any website or other seller which talks about AAAA+++ grade pearls is talking rubbish and this should be challenged).

Tahitian pearls have a distinct and separate system, established by GIE Perles de Tahiti, and the Ministere de la Perliculture of Tahiti which grades from A (finest) to D ( poor) but to avoid confusion Pearlescence uses only the A-AAA gradings throughout the website.

We also have adopted the name ‘Essence’ for pearls which are exceptional. They have been selected for highly metallic lustre, clean surface and shape, in that order. Usually only found by selecting in person. Probably under 1% of pearls will show the mirror metallic lustre we look for

Abalone Pearls

Research and new farming for abalone pearls has started in New Zealand in the last few years..

  The abalone produces a distinctive and    tunningly iridescent blue pearl but is very hard to nucleate as its blood does not clot, so any damage will kill it.There are natural (wild) abalone pearls out there, with wildly baroque shapes and a distinctive horn shape tapering from a broad and sometimes distorted and ugly base to a sharp tip


Akoya pearls come from the akoya oyster (Pinctada Fucata Martensii), which is the smallest pearl producing oyster (6cm to 8cm). This is why akoya pearls over 10mm are very rare while the normal size is about 6mm to 7mm It is a salt water mollusc.

Little akoya pearl oyster

Most cultured sea pearls are akoya pearls which are made with a bead nucleus, so that they usually have a good round shape. Big irregularities tend to be tails while less than perfect pearls have nacre with pits or convolutions. Good akoya pearls have a sharply reflective metallic lustre. Most akoya pearls come from Japan with a small production in China.

Akoya oysters like to live in water one to five metres deep and in temperatures of between 15 to 24 degrees Celsius

Modern pearl farming began properly in 1905 when Kokichi Mikimoto produced the first round farmed pearls. The company which still bears his name continues to be a world leader in the provision of the finest akoya pearls

Akoya pearls are harvested after only 9-16 months. The main thing to be aware of is that akoya pearls which are too cheap can have only the thinnest layer of nacre. Pearls with very thin nacre may even ‘blink’ which means that when rolled the nacre blinks to show patches where there is no nacre and you can see the nucleus. Below is a very bad example – the cream colour is nacre and the white is nucleus. Even when the nacre appears solid it can be very thin: peer closely and you can just about make out the thin line of the black nacre on the akoya pearl on the left (which split in half) The nacre on the pearl on the right is so thin the pearl is a ‘blinker’ .

Very thin black nacre Nacre so thin the bead is visible in places

You can see the thin akoya nacre

in these split pearls

Recently the trend for natural colour pearls has spread to akoya pearls and where once

Blue single vietnamese akoya pearl grey blue round akoya strand

every akoya pearl would have been bleached to make it white (and then often pinked to give a pink overtone) now akoya are available in delicate natural shades of pink, grey, or gold as well as a dark grey/blue which also has strong green highlights

Most white akoya are bleached, though some natural white are available. Black akoya are dyed and can look too uniform and dense in colour, while it is also hard to find gold akoya which haven’t been dyed. Suspect strong gold tones and opt for delicate blush tones

Natural pale gold akoya pearls. Natural mixed colour akoyas



Baroque pearls are strictly all non-round pearls but the term is usually applied to pearls which are not round but which nevertheless have a good rounded surface all over. Freshwater pearls are most commonly baroque as freshwater pearls are mantle-tissue nucleated instead of bead nucleated. So round pearls are the exception, although more are being produced as techniques improve. The most valuable baroque pearls are South Sea and Tahitian pearls which are produced by Blacklipped and White-lipped oysters (Pinctada margaritifera, and the Pinctada maxima).

Baroque white freshwater pearl necklace

Commercial baroque pearls tend to be bigger pearls – there is a balancing act for the pearl farmer between leaving the pearl in the mollusc with the chance of a big round pearl and the likelihood that the pearl will go out of round and become baroque and therefore less valuable – but for the buyer, you will be getting a lot of nacre for your money.

Bead Nucleation

There are two basic types of farmed pearls: bead nucleated and tissue nucleated. (The other main type classification is between cultured or farmed and natural or wild pearls)

Nucleation is the process which starts off the growth of a cultured or farmed pearl. It involves inserting something into a nacre-producing mollusc to trigger production of a pearl. This nucleus can be either just a tiny sliver of mantle tissue on its own or a sliver of mantle tissue plus a bead or other shaped foundation. In either case a nacre secreting pearl sac grows and a pearl is made within that sac.

Bead nucleated pearls include all Tahitian and south sea pearls, akoya pearls and many modern big freshwater pearls (brands Edison and Ming – see separate entry under Edison)) as well as fancy shapes such as coins or hearts.

Tissue nucleated pearls are mostly all freshwater pearls which are therefore all nacre, solid pearl. no bead inside. (Chinese and Biwa freshwater pearls)

Keishi pearls are an exception. They are the pearls formed inside a usually pre-existing pearl sac from which a pearl has been removed (think of how a balloon looks when the air seeps out over time and you get the idea of a keishi pearl.

oyster diagram

Archetypical shellfish
1 Shell
2 area of mantle tissue from which donor tissue is taken
3 mantle
4 gonad
blobs pearl nucleation placements

Mantle tissue is used because that is the area of tissue which specifically secretes nacre. It’s usually there to make the mollusc’s shell but will produce nacre wherever it is – a talent utilised by the pearl farmer.

Placement of the nucleus varies as well. Beads are placed in the sex organ – the gonad – of the mollusc and only one per mollusc. (You might think that this would stop the mollusc from wanting to reproduce but there is some research which indicates it make them more not less active!)

Tissue nucleated pearl grafts can be many to a mollusc and are placed in the mantle.

All sea pearls are grown around a bead. It used to be that beads were not used in the production of most freshwater pearls (exceptions include coin pearls for example) However the last couple of years have seen the development of bead nucleation in freshwater pearls, producing second or third graft round pearls of stunning colour, lustre and shape. High quality bead ‘nuked’ pearls are still exceptional and unusual and therefore very expensive, but can be up to 18mm.


Or sometimes biwi-

A freshwater pearl grown in lake Biwi in Japan. Biwa pearl production stopped some years ago in the lake due to pollution but some farmers are having some success with growing these rare pearls again

Stick pearls are often generically mis-described as biwa pearls. They aren’t.


White pearls are colour treated by bleaching. This applies to both akoya and freshwater pearls. Sometimes after bleaching a faint pink overtone is added as this can make the pearl more attractive

Black-lipped Oyster

Pinctada margaritifera This oyster produces the Tahitian black pearl, which is neither black, nor comes from Tahiti.


Term to describe poor quality bead nucleated pearls where the nacre does not even fully cover the nucleus. When the strand is rolled the pearls look as if they are blinking. Beware of akoya pearls which are cheap. They will almost certainly have very thin nacre which will wear through.


A pearl that is attached to the inner surface of a mollusc shell.


Often rounded on one side and flat on the other. Sometimes also called a fastener pearl . Most often used to make stud earrings, because in larger sizes round pearls can be too proud of the earlobe.



Classic term to identify the amount of gold in metal. Different metals are added to gold to harden it and make it more durable. Expressed as a fraction of 24 parts so that 24ct is fine gold or pure gold, down to the lowest standard which is 9ct in the UK, usually 14ct elsewhere.

Circle pearls

No one knows exactly why some pearls develop circles. These can be bands of colour or grooves, as the pearl has gently spun on its axis in the pearl sac. While circle pearls tend not to be the most expensive they are not as yet imitated and have stunning variety .

These Sea of Cortez drops show circles, both as grooves and in bands of colour


Natural freshwater pearls tend to be shades of white through to pale pinks and peaches and golds The intensity of the colour depends on the species and strain of host mollusc plus the farm water and food.

Colour Treatments

Many pearls are coloured treated as part of the processing between farm and retailer. There is however, now a trend towards completely natural colour untreated pearls.

Freshwater treatments

Grey – Silver nitrate and gamma radiation

Black – dyed. A good dye process will bring out a range of colours and even peacock effects Over dying will produce a heavy black monochrome. Beware of ‘tahitian black’ colour pearls which are freshwater pearls dyed to imitate Tahitian pears. Tahitian black pearls are common on auction sites

Gold Bead nucleated pearl producers are trying to emulate the deep gold of south sea pearls to produce huge valuable pearls at great prices. They are close but the colour isn’t quite right yet. Be suspicious if the pearls are too cheap for what they appear to be.

Bright deep colours – various dyes can be used to colour pearls the same as fabrics


Most akoya white pearls will have been bleached, although natural white akoya can be found. White bleached akoya pearls are often ‘pinked’ – delicate tinted to a faint pink overtone which softens the colour and is supposedly more flattering and desirable.

Black -dyed

Gold- often dyed to a deep gold which resembles gold south seas. Natural gold akoya are a much softer and paler colour

South Sea

Gold pearls are often dyed to enrich the colour to the most valuable deep gold. One strand generally looks fine on its own but in a hank the dye becomes more obvious. Always ask about dye and a reputable seller will not mind and will know.


Usually a round flat pearl shaped like a coin, also used to describe fancy hearts, squares, lozenge and other shaped pearls

Conch Pearls

Rarest of the natural pearls, conch pearls look a bit like jelly beans. They are not nacreous but have a distinctive flame pattern on the surface. The colours range from orange, through yellow to pink

Conch pearls

Cook Island Pearls

Specific group of south sea islands which produce their own distinctive pearls from Pinctada Margaritifera. The pearls show the same colours as Tahitian pearls but are softer looking in shades, while also being more grey/black than green

necklace of Cook Island pearls.

Cortez Pearls

Very rare pearls produced by one farm in the Sea of Cortez, Mexico, from Pteria sterna, the rainbow lipped oyster. (the indigenous pearl oyster). These pearls fluoresce red under UV light. The pearl colour default is a light silvery grey but, true to their name, Cortez pearls can show a rainbow of colour, including a strong mid-blue. The farm has been operating since 2004 so the total number of pearls is very small so the price is correspondingly very high.

Rainbow colours from Perlas del Mar.


Cross can be diagonal or crucifix. Some cross pearls which also have nacre between the limbs have been sold as ‘butterfly’ pearls

Peach cross pearls Butterfly pearls

Cristaria plicata

The cockscomb pearl mussel was the mollusc originally used by the Chinese when they started to culture freshwater pearls. The pearls produced are known as rice crispie pearls because of their resemblance to the cereal


Cultured is really just a jewellery trade word for farmed. It is any pearl formed after a human puts a bead nucleus with mantle tissue or just mantle tissue into a mollusc. Any farmed pearl is cultured. Any real pearl feels faintly gritty when rubbed gently on your teeth (faintly gritty, not filing your teeth down abrasive) and the drill hole tends to be very small (usually 0.7mm) (because pearls are still sold by weight at wholesale) (Natural pearls are pearls made by nature on its own, with no human activity at all -See separate entry)

Culturing Process


In freshwater mussels, insertion of only mantle tissue is enough to trigger the making of a pearl sac and therefore pearl production. It used to be that beads were usually not used. However the last five years have seen the development of bead nucleation in freshwater pearls, producing second or third graft round pearls of stunning colour, lustre and shape. High quality bead nuked pearls are still exceptional and unusual and therefore very expensive, but can be up to 20mm.

Even larger pearls are being produced with pearls nucleated with a compound which expands as it absorbs water and thereby stretches the pearl sac. These pearls, third graft, often have stunning lustre. When drilled the compound is cleaned out. The pearls are called soufflé pearls because the are hollow and lightweight for size so far.

Huge 20mm natural blue soufflé pearl.

When drilled the mud is drained away so that the pearl is hollow and light in weight.

(The name was given to them by veteran pearl dealer Jack Lynch of Sea Hunt Pearls) However most freshwater cultured pearls are still solid pearl nacre, even pearls up to 15mm. This means that they are arguably more durable but the chances of perfect round shapes are much lower

metallic white tissue nucleated freshwater pearls

While Salt water oysters will only manage to make one pearl each (which keeps up their scarcity and value) freshwater mussels are more obliging and will make 20 or more each, when tissue nucleated.

Some farms and companies are developing their own strains of mussel, selecting for quality, while other farms will buy in their mussels ready nucleated. This careful breeding is producing more strongly coloured natural colour pearls. After harvest in China pearls go from individual farms to pearl factories where they are bleached to be white pearls, or otherwise coloured or processed, drilled and sorted, and assembled into strands.


Several distinct types of pearls grow in salt waters. Farming methods are pretty much the same for all of them The process of growing sea pearls in oysters was discovered (or re-discovered as there are arguments about this) by Mikimoto in 1893. All pearls which grow in salt water start with baby oysters which are either artificially bred in a hatchery or spawn naturally then are collected by placing various lures in the water to attract the spats as they are called.


The baby oysters are grown on for two or more years until they are big enough to manage to accept a grafted bead nucleus. With all sea pearls the pearl is grown around a nucleus – a starter bead plus a tiny fragment of mantle tissue which grows to form a pearl sac around the bead. As the mantle tissue is tissue for making nacre/shell it carries on doing this, secreting nacre on the inside of the sac and onto the bead. Mantle tissue makes the pearl sac because its job normally is to secrete the mother of pearl to make the smooth and lustrous lining of the oyster’s shell. . Early in the morning of the day an oyster will receive a nucleus, it is taken out of the water and then left for about half an hour, by which time it should have opened its shell a little. The shells are wedged open. Any unopen shells go back into the water to be left for another attempt in a few days Nucleating oysters is a skilled task – even opening the shell too far can kill the delicate creature. The bead-plus-mantle tissue scrap is inserted into an incision into the body of the oyster, either at its gonad or by the connective tissue.

Inserting the bead and nucleus into the host oyster

Remarkably having a bead stuck into its sex organ seems to make the oyster more active sexually rather than less! A nucleus is a (usually) round bead made from shell and cut and polished into a smooth round -usually about 8mm in diameter for first grafting.

The oyster is secured in a clamping device in front of the operator and either the wooden wedge is left in place or a retractor which allows the shells to be forced further apart is inserted. If the oyster is opened too far it will die. The aim is for this process to take under a minute and it is reckoned that it takes a month at least for the oyster to recover. The actual process is that the grafter, working through the tiny opening between the two halves of the shell, makes n incision of about a centimetre into the oyster’s gonad or into its connective tissue then places the mantle tissue and nucleus (dipped in water and held by a suction tool) into this slit. The two insertions must be touching, or a pearl sac will not form. Then the oyster is put back into the sea. There are various ways it is held but they all work to allow the oyster to feed happily and grow. No-one knows exactly why some grafts become great pearls and others don’t. It is probably a mixture and combination of genetics, grafting skill, and growing conditions. Many farms keep a record to see who is the best grafter (!)

The implanted tissue forms a pearl sac around the nucleus and starts to secrete nacre. It will take between two and four years for the pearls to form. The tissue implant is only about 1mm square. It will form the pearl, which has no genetic relationship with the host mollusc. As long as the irritant is present the mollusc continues to add layers of nacre until a smooth lustrous pearl is formed. Only one pearl per oyster can be produced. Sometimes oysters can be re-nucleated after harvesting to produce a bigger pearl with a bigger nucleating bead, or, if no bead is used a keishi pearl can be produced (think of the inside of an inflated then deflated balloon) Oysters are fairly fussy about their conditions and if forced to open too much they will die, as they will if they are out of the water too long, get too hot or too cold, if the water in which they live becomes too saline or not saline enough (this happens when a river floods and any oysters living in the estuary may well die because of the temporary dilution of salinity.

These oysters are attached to a length of rope. Other farms use mesh or baskets

It takes about 18 months to two years to grow tahitian and south sea pearls. Tahitian pearls are required by local law to be x-rayed and have a minimum nacre depth of 0.8mm all round. South sea pearls tend to have much thicker nacre than this There is some controversy about how long akoya pearls need to stay in the water. Some are harvested after only six months but these pearls can have gaps in their nacre so the bead is visible (they are said to ‘blink’ when rolled) and they will wear out quickly. But they will, of course, be very much cheaper. The pearls are cosseted. They will be cleaned several times to remove algae, vegetable growths and barnacles, and the farmer must keep an eye on the weather conditions – some akoya farms now monitor temperature and salinity and move the oysters if conditions are not ideal.


Edison Pearls

Edison pearls are simply one brand of bead nucleated freshwater pearls from China. Bead nuked pearls started to appear five years ago and can be divided into two main categories, depending on the quality of their nacre: either smooth or rippled. From this you can split the smooth into Edison (a brand from the pioneer of this type of pearl), Ming, (the second brand, not allied to any particular wholesaler) and generic bead nucleated pearls.

(Just to remind, until a few years ago freshwater pearls were usually all nacre, with pearl growth triggered by the insertion of just a sliver of mantle tissue into a host shell. It was only sea water pearls (South Sea, Tahitian, Akoya and a few freshwaters such as coin pearls) which had a bead template nucleus as well as that sliver of mantle tissue)

Edison is the brand name given to a range of large bead nucleated freshwater pearls from one leading Chinese supplier. One strand of these pearls achieved £1/2m at auction. The pearls come from a Hyriopsis hybrid between Hyriopsis cumingi and Hyriopsis schlegeli.

The Ming pearl name tends to be applied to the better quality of generic bead nucleated pearls. It is more of a description of quality than a brand. (Edison is a brand, belonging to one pearl farmer/wholesaler. They tend to be the most expensive and can be the finest quality available in the world)

In general these new bead nuked pearls can be any quality from superb to – like any pearls – terrible quality, with pitted, ringed, thin and lumpy nacre and washed out colour with chalky lustre. That’s probably what you’ll get if you bought from an unknown seller on any auction site. Quality (and, of course, price) runs up to metallic lustred 15mm perfectly round. flawlessly smooth surfaced pearls

Necklace of 12mm to 13mm AAA Edison pearls

The very latest bead nucleated pearls natural deep mauves, lilacs and purple shades

only appeared in 2015

Pair of flawless deep gold round ming pearls -14mm

The pair of pearls in the above photo would pass as a top quality pair of South Seas any day – and are still very expensive, but not as expensive as south sea pearls.



Nearly every pearl available anywhere in the world is farmed – cultured. Pearl farms tend to be stunningly beautiful places.

Shot of the Kamoka Tahitian pearl farm on Ahe, French Polynesia

Pearl farm on Talesei Island, Indonesia…golds and white south sea pearls


Faux Pearl

A false pearl bead manufactured by coating the inside of a hollow glass sphere or the outside of a solid glass or plastic sphere with a pearlescent coating which is sometimes pearl powder. Faux is a fancy word for fake. Also called shell pearls. They are of course perfectly round in shape, with great lustre and even colour. White shell pearls are very white, which is a give-away. All fake pearls feel smooth when rubbed on the teeth and the drill holes tend to be larger.


There is a young but growing pearl industry in Fiji, and the pearls produced have a huge and stunning range of colours, mostly shifted away from typical Tahitian colours into the chocolates and earthy shades

Newly harvested, straight from the shell, Fiji pearls


A pearl grown in a freshwater river, lake or pond margaritifera mollusc. Often more irregular in shape and more varied in colour than salt water pearls freshwater molluscs are nucleated by creating a small incision in the fleshy mantle tissue and inserting a piece of mantle tissue from another mussel. This process may be completed 25 times on either side of the mantle, producing up to 50 pearls at a time. The molluscs are then returned to their freshwater environment where they are tended for 2-6 years. The resulting pearls are of solid nacre, but without a bead nucleus to guide the growth process, the pearls are rarely round.


Gamma Radiation

Gamma irradiation turns the nacre of freshwater pearls very dark, and often also imbues a metallic lustre with rainbow orient. Strangely, it has no effect on salt water nacre but will turn the nucleus dark which shows through the layer of nacre, making the pearl look grey or blueish There is no danger of radiation contamination from irradiated pearls.


or popcorn pearls have a knobbly surface which resembles..popcorn. This granulation is often mixed with patches of high lustre surface. When the Chinese freshwater pearl business was starting up most of the pearls were, at least to some degree, popcornish and oval in shape. Term also used for the earliest Chinese freshwater pearls which were called Rice Krispie pearls.

Loose, undrilled white rosebud /granulated pearls

Gold Leaf Pearls

This is the name we give to the extremely beautiful lustrous gold pearls which are natural pearls with a layer of aragonite with an incredible lustre – so it does indeed look as if a layer of gold leaf has been applied to the pearls.

These pearls show the stunning gold colour which

looks as if gold leaf had been applied to the pearl surface

Gold-lip Oyster

A large oyster (variety of Pinctada maxima) used in some countries to produce South Sea cultured pearls; it produces a yellowi nacre, and pearls that typically range from off-white to rich, deep gold in colour.

Loose undrilled gold south sea pearls waiting to be paired for earrings


An optical phenomenon which causes the hue of the pearl to change colours depending upon the angle from which the pearl is viewe. Popularly called colour-change pearls



A pearl which has only been partly drilled, as for rings or stud earrings. These sell for more than those which are fully drilled. The best have a flawless domed side.


The term hallmark is often confused with branding, but it is not a branding. Hallmarking is a specific process of assaying precious metals and marking them as having passed a required standard. It is a guarantee of quality of content. Hallmarking dates, in England, from 1300 when Edward 1 brought in a requirement for standardisation of silver for coin and wrought pieces, which were to be marked with the leopard’s head mark to show they had passed assay. Variations on the leopard’s head are still used today for sterling silver pieces marked at the London assay office, run by the Worshipful Company of Goldsmiths. Different marks are used to denote fine silver, and the various grades of gold, plus platinum and palladium. A mark will show when and in which office the item was assayed, plus what metal and who made the item. The mark is either struck to the metal (the origin of ‘making one’s mark’ as the maker can optionally still strike their own sponsor’s mark before assay or the mark can be struck by laser. All Pearlescence precious metals over the required minimum weight carries the London Assay office hallmark of owner Wendy Graham (Initials wmg in an oval cartouche).


Pearls are harvested when the pearl farmer judges that there is enough nacre. This can either be cyclical or annual depending on the weather and the mollusc – in China the traditional harvests are in the winter as it is thought that winter nacre on the outside means a sharper and more intense lustre.

The harvest is also a time to seed the new crop, as the mantle tissue from the best producing pearls will be used to start the pearls for the next crop.

While some farms (eg Cortez and the Kamoka Tahitian pearl farm) market their own pearls as a name and brand in its own right, most pearls worldwide go into processing to be mixed with others to make strands at the processing factories. Some pearl sellers will claim that all their pearls come from the farm they visited, but this is extremely unlikely as one farm will not produce enough pearls to produce a range for retail.(and it is unlikely that a pearl farm will be able to drill and match for strands)

Tahitian pearl harvest.

Hyriopsis cumingi

The triangle shell is the shell used to culture most freshwater pearls in China

Irradiation Irradiation has differing effects from freshwater to salt water cultured pearls. The gamma rays do not affect the nacre layers of a salt water cultured pearl, but in fact darken the nucleus of the pearl. An irradiated salt water pearl appears to be grey or blue. The nacre of freshwater irradiated pearls, on the other hand, if affected by the gamma rays and can become very dark. Some of these freshwater treated pearls will also have an intense metallic sheen and iridescent orient over their surface.




These are a sub-species of freshwater pearls grown only in Lake Kasumi-ga-Ura, some 40 miles northeast of Tokyo, Japan. They have a distinctive surface, like wrinkled satin. Kasumi like pearls are now being produced in China

Chinese Kasumi look remarkably like the distinctive pearls

from lake Kasumi but cost a fraction of the price

Keishi or Keshi

Japanese word meaning “something as tiny as you can imagine”, such as a grain of sand; used originally for very tiny gems that resulted by accident as part of the culturing process; now used to refer to all-nacre baroque pearls produced when something goes wrong in the process of culturing so that the seeding nucleus is ejected from the half formed pearl. South Sea kesihi pearls can be very large; Japanese keishi pearls can be minuscule. The shape ranges from resembling a cornflake (so they are also called cornflake pearls) to something more like a slightly deflated balloon. They tend to have fabulous lustre

White keishi pearls


Knots in the silk between pearls is a sign of quality in pearls. If there are no knots or the pearls are on beading wire and look stiff and without movement then they are not being assembled to show their best. The knots serve two purposes. Firstly the chances of losing all the pearls is minimised, only one or two maximum can be lost (Pearlescence always gets really annoyed at the scene in ‘Murder is Announced’ where the pearl necklace breaks and all the pearls shower onto the floor. Good for Miss Marple but very bad for pearls). Secondly each knot acts as a hinge allowing the necklace or bracelet to flex. They stop the individual pearls packing closely. Never get pearls strung onto real silk wet – this is not because the pearls will be harmed, it is very unlikely that just getting wet with water (either salt, fresh or swimming pool) will damage pearls after all, but the silk on which they are strung will rot in time especially the silk inside each pearl which is trapped and therefore takes much longer to dry. Please do wear your pearls all the time. Pearls need light oils to look their best and the oil in human skin is perfect. If you absolutely must wear your pearls in water then please let us know and we can re-string them on a very strong and water resistant synthetic silk substitute.

Play between the pearl and the knots. This is a sign that the silk may be stretching and it might be time to start thinking about getting them re-strung. We are happy to re-string pearls and will restring our own pearls at a reduced rate.

The picture shows a two strand necklace where the upper strand has been

strung unknotted onto silk and the lower has been knotted.



A blister pearl which has been hollowed out and filled with a substance and backing. Mabe pearls are often made into earrings A mabe is a hemispherically shaped pearl which is grown against the inside of the oyster’s shell, rather than within its tissue Blister pearls are worked by cutting the pearl out of the shell with a circle-bit drill. The nucleus is then removed and replaced with a resin. The back of the pearl is capped with a piece of mother-of-pearl to complete the mabe pearl.


This is a Japanese term which means before (mae) treatment (shori). It encompasses treatments used on all akoya, freshwater and some South Sea pearls. Maeshori treatments vary from factory to factory. The processes tighten the nacre and pull moisture out to enhance the lustre. This has a side effect of tending to make the nacre more brittle, so that freshwater, pearls that have been overtreated will turn chalky very quickly. Maeshori processing on South Sea pearls is very common in Japan. It makes the pearls whiter, brighter, and more saleable. One basic maeshori process is tumbling in chips of walnut shell which cleans and burnishes. This is considered so standard that it is not normally a declared treatment


Majorica or Majorcan pearl

A high-quality fake pearl manufactured in Spain by Majorica, S.A. These nuclei are dipped in high quality essence d’orient ( varnish made up of the scales from bleak, shad, herring and salmon. 2,000 fish make one litre of essence, which is an organic substance similar to uric acid.)

Mantle tissue

The special tissue inside certain molluscs which secretes nacre Metallic Lustre A pearl has a metallic lustre when the lustre is so shiny that it resembles polished metal. Metallic lustre is not a criterion in the usual grading system


What are Ming pearls? They are usually the better quality generic bead nucleated freshwater pearls, but some people throw that description at any quality of such pearls. As a quality description it is really pretty meaningless. Calling a pearl a Ming pearl does not of itself guarantee any sort of quality.(see bead nucleation and Edison for further info)

A Ming pearl necklace


A momme is unit of weight, used for silk or pearls, and you will still sometimes see pearl prices quoted as per momme – with the price given against quality. One momme is 3.75 grams and one Kan is 1000 momme



is composed of hexagonal platelets of aragonite ( a type of calcium carbonate) (in a crystalline form) and conchiolin (an organic protein substance which provides bonding). The specific lustre, iridescence, and colouring of nacre — and, therefore, of any pearl which it forms — depends on the number and thickness of the various layers, as well as on whether or not the layers overlap one another. A freshwater pearl is made up of many layers of nacre and no bead.

The layers of nacre can be clearly seen in this freshwater

solid nacre pearl which has split open


A pearl which is ‘wild’ ie one which has grown without any human activity or intervention is called a natural pearl. Natural pearls are very rare these days and so command high prices. There are still several wild colonies of freshwater mussels Margaritifera margaritifera in the UK and they are protected by law under the Wildlife and Countryside Act 1981. Selling a UK natural pearl needs a licence. These molluscs can live for over 100 years. The earliest reference in Britain to freshwater mussels is by Julius Caesar’s biographer, Suetonius, who stated that Caesar’s admiration of pearls was a reason for the first Roman invasion in 55BC.



A matched set of jewellery, which might include earrings, a necklace, brooches, rings, and other pieces.


A peanut pearl is formed when two nuclei in a seeded pearl stick and then grow together to make something which resembles the shell of a peanut.


Resembling pearl or mother-of-pearl in iridescence and lustre (or, of course, an excellent source of all things pearl)

Pick a Pearl

A marketing ploy used in some tourist shops whereby the customer selects a shell which has been pre-seeded with a pearl of some sort, and lo – there is their pearl. Look closely and the mollusc is preserved in chemicals and long dead and the pearls usually freshwater. Pearlescence heard of one operation in the UK where someone got a dyed green potato pearl and was told it was green because the oyster was sick. Pearlescence knows where to buy these seeded molluscs for under $1 a time in China. But wouldn’t.

Tinned pickled pearls………….

Nicknamed Pipi pearls. The smallest of the oceanic pearl producing oysters and possibly the direct ancestor of all of them. It produces bright, lustrous deep golden pearls but is too small to be farmed on a realistic commercial basis. The shells are only about 20mm and pearls range from 2mm to 5mm.

Pinctada margaritifera

This mollusc produces the black Tahitian pearl in French Polynesia, the Cook Islands and Australia


A very common to routine treatment especially for akoya pearls whereby the pearl, after bleaching, is dyed so that it shows a tinge of pink.


Pondslime is the name given to pearls which show an unusual golden to brown coating to their natural colour nacre. These pearls used to be either discarded as junk or dyed dark colours to disguise what was seen as a failure in cultivation but now such natural effects are valued and desirable. The effect ranges from a dull nicotine brown to dazzling gold as if the pearl has a layer of gold leaf

Popcorn Pearls

Pearls of any shape on which the surface nacre has a granulated appearance so that they look like fresh popcorn. We call them granulated pearls. Also called rosebud or strawberry pearls and in China, mao-jyue or hairy pearls.

Popcorn pearls


Any mis-shapen pearl is a potato pearl because it resembles a potato. Also called irregular pearls or nugget pearls. Cheaper potato pearls will have one flat surface but the better ones are rounded all around

Better quality potato pearls have smooth rounded surfaces and great lustre

Pteria sterna The rainbow lipped oyster which produces the pearls of the Sea of Cortez, Mexico These pearls fluoresce red under ultra-violet light.



Oval/elliptical shaped pearls. Considerably cheaper than round pearls.

Rice or elliptical pearls. Can also be drop/drip shape

Rice Crispie pearls

Chinese freshwater pearls were originally grown in the Cristaria plicata (cockscomb pearl mussel) and resembled rice crispies.

Typical rice crispie pearls


Ancient romans loved their pearls and pearl jewellery has been found in excavations. A pearl dealer was called a margaritarius

The marker for one pearl dealer, Gaius Ateilius Euhodus, is still standing just outside Rome.

Tombstone marker for Gaius Ateilius, margaritarius

Rosebud see popcorn


The more perfectly round a pearl is, the more valuable. A good quick way to assess roundness is to gently roll a strand of pearls. Irregularities will show easily to the eye

Loose undrilled white round freshwater tissue nucleated all nacre pearls



Fakes can sometimes be real pearls which have been processed to look like more valuable pearls. Popular on auction websites where people sadly buy Tahitian pearls for £5.

Two examples. The left hand pearls were described as baroque south sea pearls and the ones on the right as Tahitian blacks (this gets around the restrictions as they are describing the dye colour, not the pearl provenance) The Tahitian black pearls have some wear as they may look acceptable but the poor dyed fireballs pretending to be south sea pearls ended their days in the bin

These unhappy pearls were sold as baroque south Tahitian black – the label describes the dye

sea not the place of origin. The same stock photo

appeared at £6.70..or £7.10 from another

seller or 0.01p in an auction from a third

Note that some freshwater suppliers are working to dye big round bead nucleated pearls to resemble the finest gold south sea pearls. Individually strands look impressively close, but in a hank they look slightly ‘ear-wax’ yellow.

This photo shows loose genuine south sea pearls. Some are untreated

while others have been dyed to ‘enhance’ the colour.

Scottish River Pearls

Highly prized and very rare wild natural pearls. So protected by law that a licence is needed to sell them. The species is Margaritifera margaritifera . They are believed to live for 250 years! It is said that one reason for the Roman invasion of Britain was to gain access to the pearls.

Wild Margarififera Margaritifera pearls

Wild pearls live in several locations around the UK. All very secret

Sea of Cortez

One farm is producing mostly greys and blue shades in Mexico, re-starting a pearl history which was thriving when the Spanish invaded (see Cortez for more information)

Second Graft

What it says – a second graft happens when a mollusc is returned to the water after harvest. Its pearl sac is either re-filled, with a bead equal to the size of the pearl removed (so that the second pearl grown will be larger when that is harvested) or a keishi pearl will grow.

Seed pearls

Tiny pearls weighing under 1/4 grain, usually 3mm or less.


Generally the rounder the pearl the more valuable the pearl is.

Silver nitrate

This chemical, the same as used in photography, darkens the appearance of pearls. The chemical penetrates the layers of nacre and has a chemical reaction with light and hydrogen sulphide gas to create a rich black colour.


Generally, the bigger the pearl the more valuable, however a smaller more perfectly formed round pearl will be more valuable than a big baroque one. Pearls under 3mm in size are increasing in price as their production is falling. Pearls are measured at 90deg to the drill hole (or where the drill hole would be if undrilled)

Souffle Pearls

Very large freshwater pearls are being produced with pearls nucleated with a lump of expansive compound These pearls, third graft, can have stunning lustre and a rather keishi appearance so far. When drilled the compound and water is drained away so that the pearl is hollow and light in weight. However most freshwater cultured pearls are still solid pearl nacre, even pearls up to 15mm. This means that they are arguably more durable but the chances of non-perfect round shapes are higher.

South Sea pearls

Large South Sea cultured pearls (up to 16 mm), farmed in Australia, Indonesia, and the Philippines, range in colour from white to gold and to black. They can have a perfectly round to slightly asymmetrical shape and medium to high lustre Price varies depending on lustre. South Sea pearls are harvested after at least two years. They have a unique, satiny lustre that comes from the rapidly deposited nacre and warm waters of the South Seas. South Sea pearls also have a subtle array of colours, typically white, silver, and golden, Gold south sea pearls come mainly from Thailand and white south sea pearls mainly from Australia.

White round south sea pearl very baroque very blue south sea gold drop south sea pair



Baby oysters which are either artificially bred in a hatchery or spawn naturally and are attracted to collection points are called spat. They will be grown on until big enough to be implanted

Spat – size of a thumbnail

Sterling Silver

Sterling silver is a mix of 92.5% by mass of silver and 7.5% by mass of other metals, usually copper. The copper is added to make the metal harder. All Pearlescence Sterling silver over the required minimum weight carries the London Assay office hallmark of owner Wendy Graham (Initials wmg in an oval cartouche). All silver from Pearlescence is nickel-free.


Any long thin and stick or twig like pearl, They can be drilled at the top or middle and through the wider or narrower faces to produce different looks.

Matched large thin sticks made into earrings


The smoother and more perfect the surface of a pearl, the higher the value

Tahitian Pearls


Tahitian Pearls

are produced by the black-lipped oyster (Pinctada margaritifera). They have been produced for almost exactly 50 years now in French Polynesia, in the lagoons of remote coral atolls and islands – everywhere except on Tahiti Itself!

Kamoka pearl farm,. Ahe atoll, French Polynesia

Black Lip Oysters are now also being farmed in a small way in Australia. The oyster itself is quite large — sometimes up to 12 inches across and weighing as much as 10 pounds — which often results in much larger-than-average pearls. The pearls are unique because of their natural dark colours. Most “black” Tahitian pearls are not actually black, but are instead grey, silver, charcoal,chocolate brown, blue, purple, aubergine, pink, beige or even off-white Truly black pearls are extremely rare.

Black pearls….

Tahitian pearls are grown around a bead so are often round but can be semi round to drops as well. Circles are common, and some prefer circle pearls because they are clearly real and not imitation. Tahitian pearls go through x-ray inspection before legal export (ask to see their export certificate and confuse most jewellers!) and have a different grading system A-D where A grade are the best pearls

Third graft

Sometimes molluscs yield pearls of such quality that farmers put them back in the water for a third time. Third graft pearls will be very large indeed, and the mollusc could be ten years old.

Top drilled

Asymmetrically drilled pearls, often oval. If strung un-knotted they tend to move around against each other on the silk and then are called dancing pearls


Wearing pearls

Please do not put any hairspray, make-up, perfume or any other such substances where they could contact and be absorbed by the pearls. Pearls are a natural biological substance and are porous, so avoid anything which could be absorbed by them. We have reeled back in horror when opening envelopes for some pearls returned for re-stringing where they seem soaked in perfume.

Wish Pearls

See pick a pearl.