The Diamond Certification Laboratory of Australia (DCLA)

Term often used for a round brilliant cut diamond that is believed to be excellent across the board for proportions and overall make.  There are many different ‘ideal cuts’, the most famous being the Tolkowsky Ideal Cut. The range for ideal cut diamond parameters can often be very broad, so care must be excercised in labeling a diamond as ‘ideal cut’.

Internal imperfections of a diamond affecting the clarity grade. Diamonds grow deep in the earth under extreme pressure and temperature; under these conditions, it is rare to find a diamond that is internally flawless.

The original skin of the rough diamond that remains after polishing and is indented into the body of a diamond, not confined to its surface. An indented natural can affect both the polish grade and the clarity grade of a diamond.

Diamond grading laboratory that has no financial interest in the actual trade (buying and selling) of diamonds.

Diamond usually not polished as a gemstone, as it does not meet the minimum quality criteria for grading. Industrial diamonds are very heavily included, lacking the transparency, brilliance and life that a gem quality diamond must exhibit. Industrial diamonds are somtimes used in their rough diamond form in jewellery.  Industrial diamonds are very useful for tools, drills, lasers, abrasives, and other such uses. Only approximately 20% of mined diamonds are of gem quality.

Treatment to enhance the apparent clarity of a diamond by reducing the visibility of dark inclusions.  A precise laser beam is focused on a small dark inclusion – the black in the inclusion dissipates from the laser beam itself.  Click here to learn more about laser drilling and clarity enhancement.

International organisation founded by the World Federation of Diamond Bourses (WFDB)and the International Diamond Manufacturers Association (IDMA) to establish standard rules for diamond grading and nomenclature.

International diamond trade association committed to fostering and promoting the highest ideals of honesty and best practice principles throughout the diamond industry worldwide.

Diamond grading rules and processes that are regulated and recognised by internationally accredited bodies. Examples of these bodies are CIBJO, LMHC, World Federation of Diamond Bourses, and the International Diamond Council.

Treatment to change or artificially enhance the colour of a diamond. Irradiated diamonds are bombarded with a variety of high-energy particles that physically alter their atomic structure, thus changing their colour. Most irradiated diamonds are annealed to further modify their colour. Click here to learn more about irradiated diamonds.