Recently you may have read the story of the lady who found a natural Quahog pearl in her evening meal at the local restaurant. A small, round purple pearl which from all reports was quite nice. Do they have any value?

They are natural pearls - pearls grown through the quirks of nature and without involvement by a human - so one would expect the cost to be relatively high, yes?

Unfortunately, no. They might only be worth a few hundred dollars at best.

While these pearls are natural, unique and probably quite beautiful, they are not very rare or valuable. Many pearls have been found in meals and although special, they're probably only special to the person who almost swallowed it!

Nevertheless, they make a great keepsake, piece of jewellery and most definitely a fantastic dinner party story!

Many people have asked what are the most important factors in determining pearl quality. This is a fairly simple yet complex topic.

In my opinion, the most important quality in a pearl is lustre. Why you might ask?

It's possible to have a perfectly round, smooth, large pearl but if the lustre is poor, then the value is low. It's far better to have a slightly irregular shaped, lightly marked pearl with fantastic lustre.

How do you tell if the lustre is good or bad? Look at the pearl in natural, indirect light. If you can see a sharp and clear reflection, then the lustre is good. If the reflection is somewhat cloudy or hazy, then the lustre is poor.

The determining factors in pearl value/quality are (in no particular order):

Shape - rounder is better

Size - bigger is better

Colour - whiter is better for Australian South Seas (unless it's a true gold colour which is highly prized) and Peacock greens in Tahitian Pearls

Lustre - brighter lustre is better

Surface - smooth is better than marked

In reality, if you look at a pearl/s and you feel an attachment to them and you like them, then they are the pearls for you and they will reflect your beauty and personality.

Do you know what's inside a cultured pearl?

Cultured pearls are a unique blend of nature and skill developed through trial and error. When scientists and visionaries first starting conceptualising the culturing of pearls, they needed to unlock the secrect of how an oyster produces a pearl on its own.

As you may have seen from a previous post, a piece of mantle tissue is the catalyst for the production of nacre, which is the pearly substance on the inside of the pearl oyster shell. When introduced with a small bead, a pearl in various shapes can be cultured.

But what type of bead to use? Technicians have tried many different materials over the decades including stones, ceramics, wood, metals, lead etc. These materials were not found to be compatible for various reasons.

The material ultimately chosen came from the US and more specifically, from some of the rivers and lakes in and around the Mississippi region. Here, freshwater mussel shells grew to large enough sizes, so that perfectly round beads could be cut and polished in preparation for the seeding or grafting process.

These beads need to be precision manufactured so that the resulting pearl has the potential to be the best possible quality and shape. If the shape is out by even a small margin, then the resulting pearl may be off-round. If the surface is not smooth, then the surface of the pearl may feature marks and spots.

These same beads have now been used for a number of years and help to grow the beautiful pearls you see in retail windows and in on-line shops such as ours. The material has the same natural characteristics as the mother of pearl material and is the ideal starting point for a cultured pearl.

Sotheby’s will auction the Cowdray Pearls—a gray pearl necklace described by the Swiss Gemmological Institute as “exceptional” and meriting “special mention and appreciation”—at its Magnificent Jewels & Jadeite sale on Oct. 7 in Hong Kong.

The necklace contains 42 natural gray saltwater pearls strung and mounted by Cartier. The pearls are also significant historically. They were formerly in the collection of Viscountess Cowdray, Lady Pearson, a renowned jewelry collector in England who died in 1932. The pearls were first auctioned by Sotheby’s London in 1937. “There is probably no finer collection of pearls in existence,” said the catalog note.

The last time the pearls were at auction was at Christie’s London in 2012, where they sold for $3.35 million, a record price for natural gray pearls at auction. At the time of that sale, the strand held only 38 pearls. The original strand contained 42 pearls, but at some point while in possession of the Cowdray family, it was restrung to 38, and a pair of earrings with mounts by Cartier London was created from two of the removed pearls. After the 2012 auction, the necklace was restrung with two of the original pearls and two from another antique jewel to return it to its original design of 42 pearls. The earrings stayed in the Cowdray family at the time of the initial 1937 auction of the necklace, but are included with this lot.

“We are extremely honored to offer the Cowdray Pearls in Sotheby’s upcoming Autumn sale,” said Quek Chin Yeow, deputy chairman of Sotheby’s Asia and chairman of international jewellery, Asia. “Natural saltwater grey pearls are rarely seen at auction and the present necklace, strung with 42 superb gray pearls and of aristocratic provenance, is arguably the greatest of its kind in existence. This is an extraordinary collecting opportunity for pearl and jewelry connoisseurs around the world.”

The pearls are estimated to sell for $4.5 million–$7 million.

Natural pearls have certainly been in the news lately. But what makes them so special?

Not sure you know, but natural pearl oyster beds have been depleted by many years of over-fishing, pollution and other environmental reasons. Even a fishery such as the Australian industry, which is regulated and well managed, has an impact. In reality, pearls that are borne in nature are a freak.

Whilst many in the past have attributed pearls as 'Tears of the Gods', 'Dew from the Moon' and other wildly romantic and whimsical explanations, the real widely held belief has only just recently been dispelled. To a point that is. What is it? It's the grain of sand theory.

Up until recent times, it was believed that pearls were formed via an intrusion. That could have been a predator, small marine organism and most famously a grain of sand, that found its way inside a pearl oyster. These intrusions made their way inside an oyster and the oyster became irritated. In order to reduce this irritation, it was thought the oyster coated it in nacre to make it smooth and bearable to the host and over time, it grew larger and larger resulting in a natural pearl. Now however, scientists and pearl farmers have realised this isn't exactly true.

A pearl can only be created when there is a catalyst and this catalyst is a piece of mantle tissue near the lip of the oyster itself. Unless this piece of tissue (or cells from the tissue) is present, then no pearl can be created. When the piece of grit, intruder or organism finds its way inside a pearl oyster, it must also collect a piece of tissue on the way through or have a piece break off and float down beside it. This then replicates itself around the foreign object and a pearl sac is formed. Within this pearl sac, layers and layers of nacre are built up and so begins the formation of a natural pearl.

When you consider this in the realm of pearls, natural pearls really are a freak of nature. And when you consider the quality of some natural pearls, it's amazing these can exist.

The strand in this picture is of 3 strands of natural black pearls and sold for a record USD$5.1m.

Pearl farms are usually located in pristine, secure and remote locations. They need to be protected from various factors including pollution, theft, exposure to extreme weather elements and other factors. Fortunately, some of the locations chosen for pearl farms are among the most beautiful in the world!

Did you know that no two pearls are alike? Pearls have their own unique 'fingerprint'. So when you gift a pearl to that special someone, you can be sure that no one else, will have the same.