Diamond Information

Diamonds possess a value, both visually and economically that has endured with the passing of time. The first diamonds discovered were found in a riverbed in India around 800 BC as a result of a volcanic source that has never been found. Royalty were recorded wearing diamonds as early as 1300 AD. The first engagement ring is said to be have been given by Archduke Maximilian of Austria to Mary of Burgundy in 1477 starting the tradition of diamond engagement rings.

In 1867, a 21 carat stone discovered on the banks of the Orange River, South Africa, started a great diamond rush. Between 1870 and 1891, no less than six kimberlite pipes were discovered in Kimberley.

Diamonds have long been the symbol of love and romance. The word "diamond" is derived from the ancient Greek word adamas, which means "unconquerable". Strength and durability have made diamonds an enduring symbol of matrimony and everlasting commitment.

THE ULTIMATE GEM

Diamond types are classified by nitrogen content, namely Type I and Type II. Type I diamonds contain nitrogen while Type II diamonds are nitrogen free and are usually white or blue. Type IIa and Type IIb (blue colour) are very rare and generally thought to comprise less than 1% of all diamonds. While it is possible to obtain D Flawless diamonds from Type I diamonds, the most sought after diamonds are Type IIa Flawless diamonds. Type II diamonds have superior optical properties and have a superior overall polish to Type I diamonds.

In ancient times, incredible white diamonds were recovered in Golconda in India, and to this day Golconda diamonds have held a superior position to white diamonds produced anywhere else in the world. However, notwithstanding these Golconda gems, the Gem Diamonds Marketing Consultants and some of the world's leading Diamantaires believe that the D Flawless diamonds from Letšeng are the prize gems of them all.

ROUGH GEM QUALITY DIAMONDS

These diamonds are attractive when viewed and are the easiest diamonds to manufacture and polish for jewellery.

The value of a diamond is based on rarity.

Gem quality diamonds are based on the combination of the following characteristics:

SIZE

To a large degree size does matter, especially with large white D, E F & G colours. However, when dealing with rare fancy colours such as reds, blues, oranges and greens, even small stones are highly prized gems. COLOUR

A range of colourless, moving to lighter yellows and browns are regarded as gem colours. The closer a diamond is to colourless, the more valuable it becomes. Deeper colours of yellow and brown, as well as rare colours such as orange, violet, purple, green, pink, blue and red are referred to as fancy colours.

QUALITY

Originally gem quality rough diamonds were those diamonds without cracks, twins or large inclusions, the equivalent of the polished grade SI3 or better. Lesser qualities were referred to as near-gem and included low clivage and semi-opaque rejection material.

In today's terminology, the better near-gem qualities are included as gem quality, as it is now viewed that any diamond which can provide a polishable gem be included, regardless of the fact that more splits (sawing, cleaving or lasering) are required to achieve polishable pieces.

SHAPE

The most desired rough gem shapes are the following:

  • crystals (Sharp edged octahedrons)
  • octahedrons with some rounding to the edges and points
  • dodecahedrons
  • triangular maccles
  • rounded dodecahedral maccles
  • shapes that have high yielding forms either for rounds or fancy cuts

Less desirable gem shapes are cubes, irregular low yielding shapes and twinned or aggregated forms.

Other factors which influence the overall gem description would include stones with unattractive clouds, milkiness or colour banding/zoning.

Therefore, the most desired rough gem diamonds would be those having good colour, shape and internal clarity, without ignoring the size factor.