Turneaureite Locality: ZCA No. 4 Mine (St Joe Mine), Balmat, Balmat-Edwards Zinc District, St. Lawrence County, New York, USA Dimensions: 20.5 cm x 9.4 cm x 4.5 cm Turneaureite is a rare Apatite Group species, rich in arsenic. This large layered block contains seams of turneaureite that fluoresce bright orange under SW UV light. The piece is from the well-known ZCA No. 4 Mine at Balmat, the Co-type Locality. Not pretty to look at, but certainly a large and important New York and species rarity. — Photo: Robert M. Lavinsky · CC BY-SA 3.0
Turneaureite
Turneaureite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ca₅(AsO₄)₃Cl.
It crystallizes in the hexagonal crystal system (space group P6_3/m). It is a member of the Apatite structural group.
Key properties: Mohs hardness 5; specific gravity 3.6; White streak; Vitreous to slightly greasy luster; optically uniaxial.
IMA symbol Trr, IMA status: approved, named in 1983.
A rare component of manganiferous ores in high-grade marbles.
It is found associated with Andradite, magnetite, calcite (Långban, Sweden); magnetite, andradite, manganoan calcite (Franklin, New Jersey, USA); donpeacorite, tirodite, ferrian braunite.
The mineral was named to honor Dr. Frederick Stewart Turneaure (1899-1986), Professor Emeritus of Geology, University of Michigan, Ann Arbor, Michigan, USA.