About Pearls

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A Pearl is the only gemstone that comes from a living creature. There are no two pearls which are exactly the same. Each Pearl is unique.

The Pearl is the oldest known gem, and for centuries is was considered the most valuable. To the ancients, pearls were a symbol of the moon and had magical powers which could bring prosperity and long life. In Indian mythology, pearls were heavenly dewdrops that fell into the sea and were caught by shellfish.

Throughout history, pearls have been considered divine gifts especially suited for royalty.

Pearls are also connected with the Greek Goddess of Love, Aphrodite (Venus). The mythological tale states that when she was born and walked from the sea, she shook her hair and the droplets that descended began to harden, forming lustrous pearls.
Pearls have also been considered ideal wedding gifts because they symbolise purity and innocence. An Indian fable tells how Krishna drew pearls from the sea to decorate his daughter Pandia on her wedding day.

The 30th Anniversary is known as the Pearl Anniversary because, historically, wives celebrating their 30th Anniversary were presented with pearls.

Some cultures, such as Chinese, have used pearls medically to cure a variety of ailments, including indigestion and heart disease. Pearls have also been prescribed as a love potion and tonic for long life. Calcium carbonate, the main component of pearls is used as an antacid and dietary supplement. At the age 94, Mikimoto, founder of the cultured pearl industry stated: “I owe my fine health and long life to the two pearls I have swallowed every morning of my life since I was 20.” The calcium carbonate in pearls and shells consists of two distinct minerals with different crystal structures – aragonite and calcite. The first form of calcium carbonate secreted by a mollusc is columnar calcite. Afterwards, brick-like layers of microscopic aragonite platelets are secreted. These layers form the pearly substance called nacre. Interference colours result when light passes through the layers.

Traditional pearls are found in saltwater oysters and freshwater mussels. If pearls are natural, they are formed as a reaction of the mantle tissue to an injury caused form an attack by a parasite, worm, fish or crab. When pearls are cultured, the starter of the nacre formation is intentionally introduced by man.

There are 5 main varieties of cultured pearls all originating from different parts of the globe and formed by differing breeds of molluscs.

Akoya Pearls

The Akoya Pearl is a saltwater cultured pearl. The Pinctada Fucata Martiensii Oyster or, as it is more commonly referred to, Akoya Oyster lives mainly in the waters around Japan and China. Being a fairly small variety of Oyster, the size of pearls it can produce ranges from 2-10mm with the larger sizes being of particular rarity.
Akoya pearls have been cultured for over 100 years in Japan, but, in the 80’s China started culturing these pearls as well. Now the vast majority of smaller size pearls (5-7mm) originate from China where Japan has concentrated on the larger and more valuable sizes.
Akoya pearls can be round or baroque in shape and range in colour from very pale grey to rich yellow. Black and grey cultured Akoya pearls do not occur naturally.

Akoya are considered to be the Classic Pearls used for necklaces, earrings and other pearl jewellery, with perfect round shapes, bright mirror-like luster and neutral colours.

Australian South Sea Pearls (White)

The Pinctada Maxima Oyster is the largest mollusc of its kind and lives mainly off the coast of Western Australia. With sizes ranging up to 30cm, they are able to produce pearls from 9-18mm and occasionally even larger. An average pearl harvest contains pearls of many shapes from round to drop and even fancy shapes called baroque pearls.

After a bead nucleus is inserted into a Australian South Sea pearl oyster, it takes a minimum of two years for a pearl to form, but the growth period may be as long as four years.

Tahitian South Sea Pearls

The black pearls from the Pinctada Margaritifera or Black-lip pearl oyster, are more commonly known as Tahitian pearls. The only natural black pearl grows in this oyster. Tahitian pearls range in colour from blue/silver through to musky yellow, touching on aubergine and peacock. It’s the oyster source, not colour, that determines if pearls are called black pearls. The general rule is that the darker ones are more valuable, but now all colours are very popular.

Tahitian pearls are among the largest pearls in the world, ranging in size from approx. 8mm to 18mm.

Indonesian South Sea Pearls

A close cousin of the Australian Pinctada Maxima, the Indonesian Oyster can be differentiated by its golden lip. Due to the difference in diet and the warmer waters, these indigenous oysters produce pearls in natural clear white through to the deepest gold. It is these golden pearls that are perhaps the rarest and most valuable of all pearls cultured today. Although a close cousin of the Australian oyster, very few of these pearls are produced above 16mm with even 14-16mm fetching a premium. The harvest is the smallest of all cultured pearls and this is evident in its desirability.

Freshwater Pearls

Freshwater pearls are cultured in a similar way to Japanese pearls with the main difference being the use of a mussel, the Hyriopsis Schlegeli, in place of the ubiquitous Oyster. A piece of mantle tissue from another mollusc is grafted into the muscle where a pearl sack forms around it as it gradually disappears. This is the reason that freshwater pearls are non-nucleated. Pearls can grow to virtually any size, depending on the length of time that they are left in the water. Characteristically range in shape from very baroque to near-round.

Keshi Pearls

They are formed when an oyster rejects the nucleus during culturing. Nacre is left in the oyster which is then coated, creating a non-nucleated pearl. This is not usually discovered until the oyster is removed from the water and the pearl is removed. As there is no nucleus, the pearls are mostly baroque or semi baroque and quite small in size. The beauty of Keshi pearls is that the lustre is usually very good with a deep sheen. The rarity combined with the beauty keeps the value higher than that of a standard cultured baroque pearl.

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Round pearl shapes are the most desirable. Available in all varieties except Chinese freshwater which are more commonly just off-round or potato shaped.

The lustre or shine of the pearl is often evident of a long period of cultivation. As a pearl is left in the oyster, the lustre can deepen but so does the chance of imperfections. A lustrous pearl has more than just a shiny, reflective surface. It also has a glow from within. Pearls with a very high luster will generally show the following characteristics when viewed under a bare light with the naked eye: strong light reflections, sharp light reflections, a good contract the bright and darker areas of the pearl.

Unlike diamond grading, there is no standardized grading system for pearls. Every company in the world that grades and sells pearls is using a system that they themselves devised and created. Grades are ranging from A to AAA or AAAA.

These 7 factors affect pearl’s value (GIA): size, shape, colour, luster, surface quality, nacre quality and matching. Matching describes the uniformity of pearls in jewellery. It depends on the consistency of the other six factors. It takes time and inventory to sort and collect pearls for a single strand. That’s true even if the pearls are intentionally mismatched. Matching is not a true pearl quality factor, but it does impact value. Matching does not apply to single pearls.

Information used: GIA , Renee Newman Pearl Buying Guide 6th edition

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