Tinsleyite Locality: Bendada Quarries, Sabugal , Guarda District , Portugal ( Locality at mindat.org ) Field of view 3 mm. Depth of field is achieved with CombineZM. Specimen and photo Leon Hupperichs. — Photo: Leon Hupperichs · CC BY-SA 3.0
Tinsleyite
Tinsleyite is an IMA-recognized mineral species in the phosphate class, with the chemical formula KAl₂(PO₄)₂(OH)·2H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Leucophosphite structural group.
Key properties: Mohs hardness 5; specific gravity 2.69; Pink streak; Vitreous luster; optically biaxial.
IMA symbol Tin, IMA status: approved, named in 1983.
Moderately abundant in highly altered triphylite pods in a complex zoned granite pegmatite (Tip Top mine, South Dakota, USA). In caves.
It is found associated with Leucophosphite, triphylite, rockbridgeite-frondelite, tavorite, robertsite, jahnsite, carbonate-apatite, laueite (Tip Top mine, South Dakota, USA).
The mineral was named to honor Frank C. Tinsley (1916-1996), Rapid City, South Dakota, USA, for his efforts to preserve mineral specimens for research.