Adamant, rarely Adamas (from the ancient Greek. Αδαμας - indestructible, invincible) - so in Russia about the middle of the XV century was called the jewel of the highest hardness, diamond. Modified by the Greek name of the diamond in other European languages looked like «adamaunt, adamant, diamant, diamond». Description of his journey Athanasius Nikitin in the "Journey Beyond Three Seas" (1466-1472) is considered a literary milestone celebrated stop using the word "adamant" and "Adamas" in common usage, the Russian lexicon. They finally replaced the Arabic "Almas", having all the same ancient source. In Church Slavonic word "adamant" continued to be used, often in a figurative sense - indestructible foundation, a precious gift, a man strong will, etc.
The ancient Greeks was called Adamant particularly strong steel, including the mythical origin. In one of the Greek myths described sickle of adamant, forged by Hephaestus for Perseus, Medusa-Gorgon winner.