Tag Archives: pearl information

A

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

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

G

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.

Granulated

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

Goniochromism

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

K

Kasumi

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

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.