Tiptopite Locality: Tip Top Mine (Tip Top pegmatite), Fourmile , Custer District, Custer County, South Dakota , USA ( Locality at mindat.org ) White Tiptopite on brown Roscherite. Picture width 3 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Tiptopite
Tiptopite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula K₂(Li,Na,Ca)₆(Be₆P₆)O₂₄(OH)₂·1.3H₂O.
It crystallizes in the hexagonal crystal system (space group P6_3). It is a member of the Cancrinite, Cancrinite-sodalite structural group.
Key properties: specific gravity 2.65; Vitreous luster; optically uniaxial.
IMA symbol Tpt, IMA status: approved, named in 1983.
On fracture surfaces in earlier minerals in a complex zoned granite pegmatite.
It is found associated with Roscherite, fransoletite, montgomeryite, englishite, beryl, quartz, microcline.
The name refers to its first-noted occurrence at the Tip Top mine, South Dakota, USA.