Diamonds

The "four Cs" are -- cut, clarity, carat and colour. Most diamonds never reach the consumer market because they are too flawed (often, these diamonds are used for industrial purposes -- as an abrasive, for drill bits or for cutting diamonds and other gems). The diamonds that do make it to market are judged mainly on these four factors to determine their value.

• Cut - This term refers to the way in which the diamond has been, literally, cut -- its geometric proportions. When a diamond is cut, facets are created and the diamond's finished shape is determined. The number of facets has a direct impact on the brilliance, or "fire," of the diamond. Diamonds, as the following drawing illustrates, can be cut into many different shapes. The most popular shape is the round diamond, probably due in large part to the brilliance this shape can provide.

  The shape of a diamond can impact the brilliance and overall impression of size.

• Clarity - This term refers to the measurement of a diamond's flaws, or inclusions that are seen in the diamond. Clarity levels begin with Flawless and move down to Very Very Slight (VVS), Very Slight (VS) and Slightly Included (SI).

  Now That's a Rock!The largest diamond ever found was unearthed in 1905 in Transvaal, South Africa. The Cullinan diamond was measured at 3,106 carats -- that's 621 grams!

• Carat - This term refers to the weight of a diamond. One carat is equal to about 200 milligrams. It is important not to confuse the weight of a diamond with its dimensions. Say you have two 1-carat diamonds that are both cut in the round shape -- one may appear to be larger than the other. Certain cuts allow you to see more surface area of the diamond than others.

• Colour - In referring to transparent diamonds, the colour scale runs from D to Z, beginning with Icy Blue White and ending with a light yellow hue.  

Other unique qualities of a diamond include its transparency, luster and dispersion of light. A diamond that is created from 100-percent carbon will be completely transparent. Diamonds often contain other elements that can affect the colour. Although we often think of diamonds as being clear, there are also blue, red, black, pale green, pink and violet diamonds. These coloured diamonds are the rarest ones.

Precious Gems

A gemstone is the naturally occurring crystalline form of a mineral, which is desirable for its beauty, valuable in its rarity and durable enough to be enjoyed for generations.
 
There are more than 40 popular gem varieties and many more rare collector gemstones. Although some gemstone varieties have been treasured since before history began and others were only discovered recently, they are all nature's gifts to us.

Please enjoy surfing through our Gem by Gem list of the worlds most fascinating gemstone varieties. 

The gemstone business in the past was dominated by the big three; ruby, emerald, and sapphire. These gemstones have always been the most popular and the market for these stones is different than the market for other gemstones in many ways.

When other gemstone varieties began to be popular in jewellery, the industry got tired of calling them coloured gemstones other than ruby, emerald and sapphire. People needed a term to distinguish these other gems from the big three, since all of them can be called coloured gemstones. Unfortunately, the term they made up was "semi-precious" since the big three were often called precious stones.

The problem with semi-precious, and the reason why the jewellery industry has banned its use, is that it is quite misleading. Rubies, emeralds, and sapphires can sell for less than £100 per carat and a fine Paraiba tourmaline, for example, can sell for £20,000 per carat. That seems pretty precious, doesn't it?

For all the information you could ever need on precious gemstones go to http://www.gemstones.org/.