All you need to know about Pearls
A pearl is an organic gem, grown in an oyster or mussel.
They are almost never flawless.
Cultured pearls are produced by placing a bead, called the nucleus or irritant (usually a piece of shell or plastic), inside an oyster or mussel. The animal then coats the nucleus with nacre (see nacre below) to produce a pearl.
Pearls should always be wiped over with a damp cloth, to remove body oils, makeup and dirt before storing. Keep pearls in their own separate soft lined box to prevent scratching.
Unfortunately we are seeing more and more pearls that are being painted or filled to cover natural imperfections, (sometimes this is very hard to spot but I have seen what looks like nail polish swiped across a pearl) please take a close look at the pearls you are considering buying to check they have not been artificially treated. Your supplier should be forthcoming whether the pearls you are considering have been painted or filled, large pearls are more often painted/filled.
The value of a pearl is determined by its lustre, surface quality, shape, colour and size.
Lustre: Lustre is the most important factor when choosing pearls. It is a pearl's ability to reflect light and show depth and shine on its surface. The inner glow of a pearl and the surface brilliance defines lustre. The thicker the nacre the better the lustre. Lower quality cultured pearls surface can appear dull or chalky.
Nacre: The calcium carbonate based substance secreted by an oyster or mussel to coat an irritant, producing the surface of the pearl. the lustre and nacre of a pearl are closely related, if a pearl has a thin nacre the lustre will be low and the pearl may look chalky or dull.
Surface: The surface of pearls can be smooth to heavily blemished.
Blemish: A blemish is a surface defect on a pearl, including cracks, chips, dull spots, wrinkles, spots, holes, bumps and pits. Gem quality pearls may have minute blemishes when viewed under magnification.
Shape: It is very rare to find a perfectly round pearl, the rounder the pearl the more valuable it is, the next most valuable pearl shape is a a symmetrical teardrop. Pearls come in several basic shapes; round, near round, potato, rice, mabe. blister, teardrop, Baroque and button.
Colour: Pearls range in colour from white to black; natural colours are more valuable than dyed. The colour of the pearl you purchase is entirely personal preference. Pearls with a natural exotic colour will command a much higher price than a dyed pearl.
Size: Pearls are measured in millimetres. The larger the pearl the rarer and more valuable it is.
A freshwater pearl is a pearl that is cultured in a mussel from a freshwater lake. Freshwater pearls come in many shapes, from round to button and from flat flakes to rice, and in many different colours. Freshwater pearls are less expensive than salt water pearls as more than one pearl can be cultivated at a time in a fresh water mussel.
Salt Water/Akoya Pearl
An akoya pearl is cultured in an akoya oyster in the ocean, usually around Japan. They can be up to 10mm and grow in a limited selection of colours. If they are dark grey, bluish, violet, nearly black or intense bronze, assume they have been dyed.
South Sea cultured pearls are generally larger than the Japanese cultured pearls, and grow naturally into a variety of exotic colours by being cultivated in a variety of oysters and locations.
Tahitian pearls are a good example of naturally coloured black pearls. Natural Tahitian pearl colours include deep grey (black), purple, green, gold, and silver.
A Keshi pearl is formed when the oyster rejects or spits out the implanted nucleus and forms a 100% nacre pearl, ie one without a nucleus. Keshi pearls can be fresh or salt water and are usually small in size with widely varying shapes and colours. Due to their solid nacre content they tend to have high lustre. Keshi pearls are not considered a natural pearl as they are a bi-product of the culturing process and are not a natural occurrence. Tahitian and South Sea Keshi pearls are much rarer, as pearl farms are now X-Raying oysters and when a nucleus free oyster is found, they then re-introduce a nucleus before a Keshi pearl has time to form.
Biwa pearls are freshwater pearls; their shape is usually long and thin with a wavy surface. The nucleus is made from organic material rather than shell.
Shell Based Pearl
A shell based pearl is an imitation pearl, made by painting a shell bead with paint made from crushed pearl shell.
Fake pearls can be made from glass, plastic or resin.
- Baroque - An irregular, unusual shaped pearl.
- Blister - A pearl that has grown onto the inside surface of the oyster or mussel, dome shaped on one side and flattened on the other.
- Button - A squashed round shaped pearl where one side of the pearl is flattened.
- Mabe – Grown by gluing a plastic nucleus to the inside surface of an oyster or mussel, resulting in a domed shape with a flattened back.
- Potato Shape – Slightly irregular oval shape resembling a potato; most potato shaped pearls are freshwater from China.
- Rice Shape - A regular, oval-shaped pearl that resembles a grain of rice; most rice pearls originate from China or the United States.
How to Tell Real Pearls from Fake Pearls
The following list can help you determine if a Pearl is real or not.
- Real pearls are not perfect and have ridges, bumps or pits in and on their surface. Examined with a magnifying glass, irregularities of genuine pearls will be apparent. Pearls vary in size and shape on the strand and will also not be perfectly round; unless they are very high quality and very expensive.
- Tooth Test; (NOT 100% reliable) rub the pearl over your teeth; a real pearl feels gritty while a faux pearl feels smooth. Alternatively pearls can be rubbed against each other and you will feel the same results (faux pearls can be made to simulate a real pearl and some very high quality real pearls will feel very smooth).
- The Light Test; hold the pearl strand up to sunlight or under a very bright light. Unless they are of very high quality, colour will not match perfectly on real pearls.
- Feel the weight: real pearls are heavier than plastic, resin, or hollow glass pearls, although good glass fakes may have the same weight as real pearls.
- Look at the hole; the hole in real pearls will be small. Fake pearls often have larger holes and the coating of fake pearls is more likely to flake/peel/chip near the hole, than on a real pearl. Holes of fake pearls sometimes have a rounded indent, while real pearls are mostly flat near the hole. Examining the hole is also good check to see if they are dyed.
- Have pearls X-Rayed and checked by a gemmologist.
When cut in half, you will see a real pearl's true nature. Natural pearls are made of layering nacre. When man-made pearls are cut in half, the coating tends to flake away from the cut.
How to Dye Your Own Pearls
You can dye genuine or faux pearls by using commercially available fabric dyes. Follow the instructions on the pack and check for suitability by following the check list below:
- Colour test before dying the whole strand. Record the process for an exact colour match.
- Check the colour does not change/fade when exposed to sunlight. A test over an entire day is sufficient.
- When dying while still on the strand be aware colour may be more intense around the edges near the hole.