Turquoise is an ornamental stone mainly made up of copper and aluminum. It is formed when water runs through copper-rich rocks. The turquoise used by Van Cleef & Arpels is carefully selected for its lively, radiant color ranging from light or medium blue to intense blue.

The Maison mainly selects turquoise that is pure blue and contains few inclusions, which is a true challenge for the lapidaries since most stones contain visible brown veins.
Because of its nature and structure, the color of turquoise evolves over time, particularly when exposed to acidity and heat. Therefore, the Maison chooses turquoise, in which its color has first been protected by a stabilization process, while in its natural state.