Diamond and Gem Information 

Diamonds

      Diamonds occur in a variety of colours in nature, ranging from white to pink, red, yellow, and blue, but the

      white stones are the most readily available. They are graded by an international set of standards, commonly

      called the "Four C’s". These are Carat weight, Colour, Clarity, and Cut.

      Carat weight – recorded in carats, or fractions of a carat. The carat is divided into 100 "points", therefore,

      for example, a stone weighing ½ a carat can be described as either ½ a carat, 0.50 carats, or 50 points – they

      are all the same weight.

      Colour – this is  a measure of the relative whiteness of the diamond, and is recorded on a scale ranging from

      "D" (whitest, colourless) on down through the alphabet, progressively showing more tinting (usually yellowish,    

      brownish, or greyish) the further down the stone is graded. In everyday terms, "D" graded stones are absolutely 

      colourless, "E-G" are very white, and "H-I" are a good, near-white grade. Anything below "I" in colour will

      show tinting when compared to a higher-graded stone, consequently keeping to "H-I" or better in colour is

      highly recommended. Stones that are very brown or orangish are often called "champagne" or "cognac".

      Clarity – this is a measure of the presence (or absence) of any faults, flaws, blemishes or inclusions in the

      diamond. These can be small cracks or flaws, flecks of carbon left over from the diamond’s formation, or even

      other, smaller diamond crystals. The system of clarity grading is as follows :-

            FL/IF – Flawless & Internally Flawless. Rarely encountered.

            VVS1 or 2 – (very very small) - inclusions are so small as to be extremely hard to find with 10x

                                  magnification (often graded with a microscope)

VS1 or 2 – (very small) -  inclusions are very hard to find with 10x magnification

            SI1 or 2 – (Slight Imperfection) – flaws are invisible to the naked eye, but not difficult to find with             

                                 10x magnification

            P1 or 2 (also called I 1 or 2) – flaws are visible to the naked eye, & obscure the brilliance of the gem.

      As the presence of flaws and inclusions can affect the brilliance of the diamond, it is highly recommended to

      choose a diamond of clarity SI1 or better to maximise brilliance.

      Cut – This is the quality of a stone that is most often overlooked. Diamonds are cut to very exacting proportions

      to maximise their brilliance – any deviation from this “ideal” proportion will result in a loss of brilliance.

      An ideal-cut stone will reflect back nearly all the light that falls into it - stones that are too shallow or too deep

      lose light “leaking” out of the back of the stone, and so aren’t as brilliant.

      A high-quality diamond, one sufficiently highly graded as to merit a certificate, will qualify highly on all the

      above standards. Cheap, discounted diamonds of the type sold by mall-style retail outlets, are rarely, if ever,

      of this quality. The decision of which diamond to buy is affected by the customer’s wishes – if price is

      paramount, then there will be an inevitable compromise in quality. Many diamonds sold cheaply in retail stores

      in Australia are of such poor quality that they would have been used for tipping sawblades a few years ago.

      The rule governing buying diamonds is a simple one – if it seems too good to be true, it probably is.

      Superior quality commands an appropriately higher price, while low prices are a virtual guarantee of inferior      

      merchandise.

Sapphires

      Sapphires are mined in many parts of the world, ranging from Africa to Australia and Sri Lanka ( Ceylon ),

      and come in a rainbow of colours. Although most people are familiar with the blue varieties, they also come

      in green, white, pink, gold, bi-colours (green/blue, green/gold etc), and even ones with stars floating in them.

      Along with their ruby cousins they are second only to diamond in hardness, and so make wonderfully durable

      gems. Sapphires are excellent value, as you can get quite a large stone for a moderate price.

      One thing to bear in mind, though, is that virtually all sapphires on the world’s markets have been treated

      in some way, the most common being heat-treatment. This has the effect of improving the colour and clarity

      of lesser quality stones and making them much clearer, cleaner-coloured, and attractive. They can also have

      been treated by diffusing compounds into the surface to change the colour.

Rubies 

      A large ruby of fine quality can command a price higher than that of a similar quality diamond.

      Historically the best varieties have come from Burma (Myanmar), but they are also found in Thailand,

      Madagascar, Ceylon (Sri Lanka) and Tanzania . Along with sapphire they are of the corundum family, and

      as such are second only to diamond in hardness. Colour ranges from the deepest ruby-red, known as

      pigeon-blood red, to many other shades of red showing tints of pink, brown or orange. Treatments include

      heating (as in sapphire), and also filling of fractures to produce artificially clearer stones.

Emeralds

      The finest emeralds in the world are mined in Colombia, in South America, but they also come from Russia,

      South Africa, Zimbabwe, Nigeria, Madagascar, and Mozambique . Effectively, all natural emeralds contain

      quantities of flaws, ranging from few to so dense as to make the stone appear milky. These faults can have the

      effect of making the stone prone to fracturing or chipping, as well as causing them to be somewhat porous.

      Consequently they need to be treated gently, avoiding all possible knocks and bumps. It is also a good idea to

      not put them into washing-up water, as the greasy water can carry oils and fats into the stones via the fractures.

      These fractures are utilised in the most common treatment – oiling. The stones are soaked in a light natural oil,

      which soaks into the fractures and disguises them. Other treatments include fracture-filling, where epoxy resins

      are injected into the fractures so as to disguise them from view.