Outstanding sharp silvery crystals of a mixture of the very rare S-rich selenides paraguanajuatite and laitakarite from a Russian locality (Srednyaya Padma Mine, Velikaya Guba, Zaonezhie Peninsula, Karelia Republic, Russian Federation) in a completely analyzed specimen by SEM/EDS. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Paraguanajuatite
Paraguanajuatite is an IMA-recognized mineral species in the sulfide class, with the chemical formula Bi₂Se₃.
It crystallizes in the hexagonal crystal system (space group R-3m). It is a member of the Tetradymite structural group.
Key properties: Mohs hardness 2; specific gravity 6.2–7; Metallic luster.
IMA symbol Pgj, grandfathered status — known before the IMA’s founding, named in 1948.
Intergrown with guanajuatite in contact metamorphic as well as in hydrothermal veins (Santa Catarina mine, Mexico).
It is found associated with Guanajuatite, bismuthinite, ferroselite (Santa Catarina mine, Mexico).
The name comes from the supposed relation to guanajuatite.