Turquoise – Natural, Cabochon, Blue

Turquoise is an idiochromatic gem. This means it derives its color from essential components of its chemical formula. The combination of copper and phosphorous give turquoise its characteristic blue color. (However, these elements in other gemstones may cause different colors. For example, copper in cuprite creates a red color). Gold and enamel ring with turquoises, probably Italian work from the 18th century. From the collection of the Hallwyl Museum, Stockholm, Sweden. Photo by Helena Bonnevier. Licensed under CC By-SA 3.0.

Article: Gem Formation: How are Gemstones Created?

Credit: Helena Bonnevier