branch in Geneva in May 1995. Source : Nina West, Artfact.com/Forbes.com/Christies
Type of Diamonds
Natural diamonds are classified by the type and quantity of impurities found within them.
Type Ia - This is the most common type of natural diamond, containing up to 0.3% nitrogen.Clustered nitrogen atoms. Colourless to Yellow. 98% of all diamonds are Type Ia.
Type Ib - Very few natural diamonds are this type (~0.1%), but nearly all synthetic industrial diamonds are. Type Ib diamonds contain up to 500 ppm nitrogen. These diamonds about 0.1% prevalent.Isolated Nitrogen Atoms. Orange, Orange Yellow to Brown.Depending on the precise concentration and spread of the nitrogen atoms, these diamonds can appear deep yellow (”canary”), orange, brown or greenish.
Type IIa - This type is very rare in nature. Type IIa diamonds contain so little nitrogen that it isn’t readily detected using infrared or ultraviolet absorption methods. No specific colour centre.Yellow, Brown , Pink and Purple Type IIa diamonds have been documented. These diamonds are 1% to 2% prevalent.These diamonds can be considered as the “purest of the pure” - they contain no, or minuscule amounts of impurities, are usually colourless, highly transparent and can be a higher colour grade than D.Diamond Imports recently sold a round brilliant 1.36 carat D IF Ex/ Ex Type IIa.
Type IIb - This type is the rarest in nature. Type IIb diamonds contain no measurable amounts of nitrogen (even lower than type IIa) that the crystal is a p-type semiconductor.These diamonds contain no nitrogen - but they contain boron, which absorbs red, orange and yellow light. These diamonds therefore usually appear to be blue, although they can also be grey or nearly colorless. All naturally blue diamonds belong to Type IIb, which makes up 0.1% of all diamonds.
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Diamond Imports
