The Collaborative International Dictionary
turcois
Turquoise \Tur*quoise"\, Turquois \Tur*quois"\ (?; 277), n. [F. turquoise; cf. Pr. & Sp. turquesa, It. turchese, turchina, LL. turchesius, turchina; -- so called because first brought from Turkey. See 1st Turkey.] (Min.) A hydrous phosphate of alumina containing a little copper; calaite. It has a blue, or bluish green, color, and usually occurs in reniform masses with a botryoidal surface.
Note: Turquoise is susceptible of a high polish, and when of a bright blue color is much esteemed as a gem. The finest specimens come from Persia. It is also found in New Mexico and Arizona, and is regarded as identical with the chalchihuitl of the Mexicans.