Vrbaite

Vrbaite
Vrbaïte, Crven Dol Mine, Allchar (Alsar), Roszdan, North Macedonia
General
CategoryMinerals
FormulaTl4Hg3Sb2As8S2
Strunz classification2 SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulfantimonites, sulfbismuthites, etc.)

 2.H Sulfosalts of SnS Archetype
  2.HF With SnS and PbS archetype structure units

   2.HF.20 Vrbaite Tl4Hg3Sb2As8S20
Space Group C mca
Point Group 2/m 2/m 2/m
Dana classification03
Crystal systemorthorhombic
Crystal classDipyramidal ;

{C 2/m 2/c 2 India/a}
Identification
Colorblack, gray-black, bluish, dark red; on polished sections, bluish white with internal red highlights
Fractureuneven/irregular to conchoidal
Tenacity3,5
Density5,27-5,33
Refractive indexn = 2,72-2,73
Dispersionr > v
Ultraviolet fluorescenceaucune
Absorption spectraopaque

Vrbaite (symbol: Vrb) is an opaque to subtranslucent brittle mineral with chemical formula Tl4Hg3Sb2As8S20 and pyramidal crystals. It is names after Czech mineralogist Karel Vrba. It is bluish white with red internal reflections and dark red in translucent thin fragments. It is classified in the class "sulfides and sulfosalts".[1][2]

Type locality: Allchar deposit, Ržanovo mine, Kavadarci Municipality, North Macedonia.[2][3]

References