Turquoise – Turquoise is a semiprecious and typically opaque phosphate mineral which displays a waxy luster and grows in massive nodules. Turquoise can range from robin egg blue to green-blue. Each turquoise mine produces specimen that have their own distinctive characteristics. The color and depth of turquoise depends often on the copper content and other included metals. The appearing natural color can also shift depending on locality of the mine and the degree of weathering of Turquoise exposed to water or air.