COLORed DIAMONDS are visibly different from any colored gemstones such as rubies or sapphires. Their diamond brilliance easily sets them apart. On the other hand is there any way of telling natural fancy color diamonds apart from their color enhanced counterparts? Well, the answer is that there really is no way of telling them apart by sight alone. Only a trained professional can tell the difference and by using special implements.
The two main methods of identifying color-enhanced diamonds are color zoning and spectroscopy. Color zoning can provide an indication of probable color enhancement, but only spectroscopy, a procedure done in a trade lab by a trained gemologist, will give a conclusive answer on the origin of a diamond’s color.
It is worth mentioning that, although it is very difficult to tell naturally colored diamonds and enhanced diamonds apart, we do not encourage the unethical representation of color enhanced diamonds as natural. We always provide a written statement to prove that our diamonds are color enhanced on all communications and recommend our customers to do the same.
IMPORTANT: Radioactive stones should be considered ‘rogue’ – their sources should be brought to the attention of authorities, and the stones should not be sold to the public under any circumstances.
Although common sense would suggest it should be easier, identifying coated diamonds can be just as difficult as identifying irradiated diamonds. When viewed face up their coloration will be evenly distributed, as the color is placed only on the pavilion side.
Reflected diffused light shone onto the pavilion side will reveal an iridescent, film-like coating. Color zoning is the easiest way to trace any form of coating, however. In high magnification pavilion facet junctions may show some damaged film or random colorless spots, which would again reveal the origin of their color.
Another simple, if destructive, way to test for coating is by immersing the diamond in concentrated acid. So far none of the coatings on the market are resistant to acid, so this will result in corrosion of the coating.