The value of a pearl is determined by the following factors:
Lustre – This is the glow or shine of the pearl.  Excellent lustre gives you the sense that you are looking into the pearl and that it has an inner glow.
Surface:  How clean or unblemished the surface of the pearl is. 
Colour:  Although a personal factor some colours are more expensive than others by virtue of their rarity.
Shape:  Also a personal factor but the round and tear drop shape are the most expensive.
Size:  As with any gem size is a factor in determining price.  As with all gems though bigger does not mean better.

It is worth noting that as yet there is no internationally agreed grading system.  That is a set of numbers and letters that describe all the factors above on an agreed scale.  So for example if you are offered an A grade pearl, it is a meaningless description if the full scale is not know e.g. “A” may be the second lowest if the grading scale is B, A, AA, AAA, AAAA.  Also what part of the pearl is the A describing – the lustre or surface.  So be sure to enquire about the whole grading scale when discussing pearls with a seller.

At The Courthouse Collection we work with

Cultured Freshwater Pearls,

Cultured South Sea pearls both from Australia and Indonesia

Cultured Paua Mabe Pearls from New Zealand.

We are please to have direct supply relationship with Pearl Farms here in Broome, New Zealand and China.  So you can be sure of the authenticity of our product.

Pearls have been around since the dinosaurs and were mans first precious gem.  Long before gem stones could be cut and faceted pearls were a revered symbol of status wealth and power.  Myths about their origin abounded from tears of the moon to dew drops caught by oysters at night. 

Pearls are organic gems produced by pearl oysters and freshwater mussels and some other molluscs.  All pearls are made of “nacre” a crystalline structure of calcium carbonate knows as argonite.  It is the way this structure allows light to penetrate, reflect and refract that makes pearls such a unique and beautiful gem.  A pearl oyster or mussel will coat any irritant that it cannot expel with aragonite to smooth away the irritation.

Today just about all pearls are “cultured”.  That is, man has introduced an irritant into the animal to stimulate their natural response of coating the irritant with nacre.  Conversely a natural pearl is the same process but nature introduced the irritant.  Contrary to popular belief is was hardly ever a grain of sand but rather parasites and other small water born animals that became trapped in the oyster or mussel that would produce a natural pearl.  Gem quality Natural pearls are extremely rare and valuable and were the source of the worlds pearls before the culturing process was commercially made successful in Japan in the early 1900’s.  To find a gem quality natural pearl the odds are about 1 in 5000 shell.  That is a lot of dead animals for one pearl.  Many “natural pearl” shell grounds were over fished into virtual extinction. 

Image showing natural freshwater pearl colour

Grown mainly in China, Japan and USA

Grown mainly in Australia, Indonesia and Philippines

Grown mainly in Tahiti

Grown mainly in Japan and China

Regardless of their origin gem quality natural pearls are rare and you are unlikely to find them in the general market place

These man made beads have many names under which they are marketed.  Here are a few:

a bead coated with a varnish that contains ground pearl shell

Established in the 1890’s in Spain

The correct term to describe imitation pearls of any kind.

A cultured Freshwater pearl is grown in a freshwater mussel in lakes and rivers.  The freshwater pearl typically does not have a seed or nucleus making it an all nacre pearl.  They are nucleated (started) with a small piece of mantle tissue from a donor mussel.  This piece of tissue is implanted into the mantle flesh of the live mussel to stimulate nacre production.  The organic nucleus dissolves away over time and thus gives you a seedless or solid nacre pearl.  This means to create large pearls, say over 10mm, it may take over 10 years for the pearl to grow.  More recently some freshwater pearls have been seeded with a nucleus to more easily produce larger pearls. 

Depending on age and size one mussel can be seeded with between 20 and 60 nuclei and this is one of the significant reasons why Freshwater pearls are so affordable.  Another contributing factor to this pearls affordability is the ease of farming these mussels in easily accessed lakes, rivers and man made lagoons.  The pearls come in a wide range of natural colours from white cream grey to many shades of pink and apricot.

There is also a large range of treated/dyed colours.  These pearls are soaked in a dye bath and may take up to 3 months to absorb the dye.  The dye is absorbed into the pearl and is not a coating.  Freshwater Pearls are not grown in Australia.

Cross sections of pearls showing dye absorbtion.

A salt water pearl is created by the introduction of a man made nucleus that is surgically implanted into the soft tissue (gonads) of the oyster with a graft of mantle tissue from a donor oyster. The tissue graft grows to cover the nucleus and coat it with nacre.  It is a very specialised operation and many seeded oyster fail to produce a pearl. The size of the nucleus depends on the species and age of the animal. The Akoya oyster is relatively small and typically produces pearls from 6-9mm.  These days, due to pollution and animal health factors, the Akoya has a thin coating of nacre of approx a millimetre or less.  The South Sea oysters may lay down between 2 to 4mm of nacre over its 2 year growing period. The oyster Pinctada Maxima also grows to the size of a dinner plate and so can take very large nuclei. The pearls typically range in size from 8 to 16mm but larger pearls up to 20mm and over are also harvested.

Mabe pearls are created by gluing a shape onto the surface of the oyster shell.  The object cannot be moved so is coated with nacre as if it were part of the shell.  To harvest and prepare the pearl for sale it must be hole sawed out, the mould removed, the nacreous shell filled with resin and then backed with a piece of mother of pearl shell.  Mabe’s are an affordable way of getting size and uniform shape.

There is much more to this unique gem that we would like to share with you. To achieve this The Courthouse Collection is currently creating a free walk through tour in our Broome Gallery explaining and exploring the world of pearls, its types, terms, methods and history.  We expect to launch this in early 2010.  In addition to this we will create a website www.thepearlinformationcentre.com.au as a resource to anyone wanting to learn about the world of pearls.  This we hope to have finished by the end of 2009

To look after your pearls there are a number of things you need to be aware of.  One way of putting part of your pearl care is “Pearls on last and off first”.  Pearls are porous so absorb chemicals such as perfume, hairspray, lotions, sweat etc.  If not cleaned off these contaminates will affect the lustre and eventually discolour the pearl.  The other care aspect of pearls to remember is that as a gem they are relatively soft so will scratch against hard items. 
So to the do’s and don’ts

• Do not wear them in the shower.  It is not the water that’s a problem, it is the soaps and shampoo’s etc.
• Avoid contact with all cosmetics, lotions etc
• Do not leave in the sun
• Pearl rings are best as dress rings as daily wear inevitable leads to them being knocked and damaged.
• Clean your pearls regularly to remove sweat and other build up.  To clean, wipe with a soft damp cloth and then dry with same.  If wearing your pearls often then occasionally clean gently in some warm soapy water and dry well.
• Pearls strung on silk should be restrung every 12months or so as the silk does deteriorate over time.
• Store your pearls flat and away from other jewellery as metal and gemstones can scratch the pearls. 
• Pearls are actually 3-4% water so do not leave them in hot conditions.  For example in the car.