Turquoise is a hydrated copper and aluminium phosphate. The colour varies from blue to blue-green. Turquoise is often mottled with cream or brown veins. Furthermore, the name “turquoise” comes from a confusion : when Venitian merchants brought this stone in France, it was called “Turkish stone”, from Turkey whereas it was from Persia. Besides, the finest turquoise stones are found in Northeast Iran ; there are other deposits in Afghanistan, Argentina, Australia, Brazil, China, Israel, Mexico, Tanzania and in the USA.