Home > American Minerals IV – August 26 > MS1642 Turquoise crystals

Turquoise crystals

Turquoise is a hydrous copper aluminum phosphate, known since ancient times. Turquoise derives its name from French for Turkish, since the original material followed ancient trade routes from Persia through Turkey (Pogue, 1915). Turquoise usually forms seams and nuggets admixed with clay. The typical admixture with clay, combined with minute grain size, led to much early confusion about turquoise chemistry (Pogue, 1915). The discovery of free-standing turquoise microcrystals in Virginia allowed resolution of the mineral formula (Schaller, 1912). Modern definitions of turquoise and related species are given in Foord & Taggart (1988). Crystallized turquoise remains a rarity worldwide, perhaps still best known from Virginia.

This specimen consists of a schist matrix with a 4 by 2.5 cm coverage of tightly intergrown turquoise crystals. The crystal size is even throughout, and around 0.5 mm. Note this specimen has a sawn backside. This specimen was part of the Charles Trantham (1936-2020) estate.

Price: $175

Item code: MS1642

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