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 [cs]. 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]
Quick Facts General, Category ...
| Vrbaite |
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| Category | Minerals |
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| Formula | Tl4Hg3Sb2As8S2 |
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| Strunz classification | 2 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
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| Dana classification | 03 |
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| Crystal system | orthorhombic |
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| Crystal class | Dipyramidal ;
 
{C 2/m 2/c 2 India/a} |
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| Color | black, gray-black, bluish, dark red; on polished sections, bluish white with internal red highlights |
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| Fracture | uneven/irregular to conchoidal |
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| Tenacity | 3,5 |
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| Density | 5,27-5,33 |
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| Refractive index | n = 2,72-2,73 |
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| Dispersion | r > v |
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| Ultraviolet fluorescence | aucune |
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| Absorption spectra | opaque |
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Type locality: Allchar deposit, Ržanovo mine [mk], Kavadarci Municipality, North Macedonia.[2][3]
