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Archive for April, 2006

Gem of the Month: Diamond

Posted April 2, 2006 By AussieSapphire

diamonds.jpgThe gemstone for April is diamond – truly the “King of Gems”. Also representing a 60th anniversary, diamond is given as the birthstone for April or the zodiac stone for Taurus.

Gemmology Matters: With a chemical composition of C, diamond is simply a transparent crystal of the element Carbon. The very strong network of tetrahedrally bonded carbon atoms is the reason for the hardness of diamond. Measuring 10 on the Moh Scale, diamond is the hardest naturally occuring substance and is ideally suited to jewellery, particularly when worn everyday.

Diamond is an excellent gemstone with with a wide range of colour (white or colourless being most popular), excellent lustre and high refractive index meaning a well-cut diamond will show great fire and brilliance. Having said that, diamond is not invincible and can be damaged. Diamond has perfect cleavage and so is vulnerable to splitting along a cleavage plane if hit in the right spot. Good cutters will orientate the crystal to minimise the chance of this happening.

Diamonds are predominantly mined in Africa although other countries also have significant deposits. Australia is also a major producer with the main area being the Kimberly region of northern Australia – the Argyle Mine being most famous for its unique natural colour pink diamonds. Diamonds are also found, although in only very small quantity, in the New England region of NSW (near Copeton and Bingara) – this area is currently subject to commercial testing by Cluff Resources.

Diamonds are valued according to a grading system based on the 4 C’s – Colour, Cut, Clarity and Carat (or weight). There are many resources on the internet describing this system and many expensive diamonds will be sold with a grading certificate as price is largely determined by the grading results. The links above provide a starting point for researching diamond grading.

Mythology and Lore: The name diamond derives from the Greek work “adamas” meaning invinvible. Many ancient cultures have sought to explain diamond’s superlative properties through divine or mystical affiliations. Perhaps the earliest symbolic use of diamond was as the eyes of Hindu devotional statues – these diamonds were cherished as gifts from the gods. It is not known when diamonds were associated with divinity but early texts indicate that it was recognized in India since at least 400 BCE. It is said the Greeks believed diamonds were tears of the gods while the Romans believed they were splinters of fallen stars.

diagroup2.jpgWestern cultures have used diamonds to symbolise fearlessness and virtue although they are also associated with power and wealth due to their high value. Today, diamonds are used to symbolize eternity and love – accordingly, they are a popular choice for engagement rings. The popularity of this modern tradition can be traced directly to the marketing campaigns of De Beers, starting in 1938. Prior to the De Beers marketing campaign, engagement rings had no one particular stone associated with them.

Alternatives in White: Although diamonds come in a variety of colours, white (or colourless) is still the most popular. There are a number of alternative gemstones in white – these are all more affordable but all are inferior in some way to diamond. Gems used as alternatives to diamond include sapphire (or colourless corundum), zircon, topaz and quartz. Diamonds also have a number of synthetic imitations of which cubic zirconia is the most commonly used (not to be confused with zircon which is a natural gemstone). Moissanite is a newer synthetic used in place of diamond. Beware of misleading names such as “Killicrankie Diamond” or “Alaska Diamond” – these refer to topaz and quartz respectively . See here for more information on diamond simulants.

Links of Interest:
A comprehensive article on diamond at Wikipedia
Argyle Diamonds from Australia – company website and gemmological information.
Diamants Infos – the Universe of Diamond
Emporia State University – Everything about Diamonds

Remember that while we unfortunately do not produce diamonds from our own mine, we can source diamonds to your specifications if you would like to add diamonds to your order. Just contact us for a quote anytime.

That is all for now from Aussie Sapphire

Blue Sapphire Treatment Issue

Posted April 1, 2006 By AussieSapphire

Just a quick post to inform our customers of the latest news in the Blue Sapphire Beryllium treatment issue that has been influencing the sapphire market recently.

Hot off the press from the AGTA GTC's Laboratory is this update for March 29, 2006:
Beryllium-Treated Blue Sapphires by Garry Du Toit, Richard W. Hughes & John I. Koivula

Unfortunately, it appears that our previous hopes that the presence of beryllium in some blue sapphire was the result of contamination appear to be wrong. Concentrations of beryllium in many of the tested stones were high enough to indicate deliberate introduction of this checmical and not accidental contamination. The disappointing thing about this affair is that once again, disclosure in the marketplace was inadequate and the labs had to play a catch-up game to deal with this new treatment issue.

The AGTA is now stating that where evidence of long term/high temperature treatment is found that further testing is required to detect the presence of foreign elements (such as beryllium).

For more background on this issue, we recommend readers look at the AIGS article published in March 1, 2006 by Vincent Pardieu – Understanding blue sapphire heat treatment: Introduction to the beryllium issue.

Both articles have a number of links to other pages containing relevant information – great reading for those interested in this subject.

Here at Aussie Sapphire, we would like to assure customers that we will always disclose details of treatment status of all gems from our own mine (and imported gems where this information is available). We sell our rough fully natural (unheated or otherwise enhanced) and cut gems will be sold fully natural (unheated) or with basic heat treatment only.

We should point out that basic heat treatment is done at a lower temperature and for only a short time compared with the long term/high temperature treatment (sometimes called UHT or ultra-high temperature) involved in the latest controversy. No chemicals are introduced during the heating process and we believe that this method which has been used for centuries on sapphire is an acceptable form of treatment if fully disclosed to the customer.

We plan to keep the Treatment Page of our website up to date with these developments so customers can learn more about this issue – breaking news will be published here on the Blog first and moved to the Treatment Page as time permits. This new issue has already had a significant impact on the sapphire market world-wide and we will keep you informed as we learn more about this.

cheers for now from Aussie Sapphire