Sulfhydrylbystrite
Sulfhydrylbystrite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₅K₂Ca[Al₆Si₆O₂₄](S₅)²⁻(SH)⁻.
It crystallizes in the hexagonal crystal system (space group P31c). It is a member of the Cancrinite, Cancrinite-sodalite structural group.
Key properties: Mohs hardness 4.5–5; specific gravity 2.391; Yellow streak; Vitreous luster; optically uniaxial.
IMA symbol Shbys, IMA status: approved, named in 2015.
Occurs as metasomatic lenses in dolomitic marble replacing lazurite.
It is found associated with Lazurite, diopside, calcite, phlogopite, pyrite.
Reflects the chemical relationship with bystrite and by analogy to carbobystrite, a prefix sulfhydryl, for its distinctive chemical difference from other members of the group.