| Hemihedrite | |
|---|---|
 Red phoenicochroite and orange hemihedrite microcrystals richly cover the matrix | |
| General | |
| Category | Chromate mineral |
| Formula (repeating unit) | Pb10Zn(CrO4)6(SiO4)2(F,OH)2 |
| IMA symbol | Hhe[1] |
| Strunz classification | 7.FC.15 |
| Crystal system | Triclinic |
| Space group | P1 (No. 2) |
| Unit cell | a = 9.49, b = 11.44 c = 10.84 [Å]; α = 120.5° β = 92.1°, γ = 55.83°; Z = 1 |
| Identification | |
| Color | Bright orange, henna-brown, to almost black |
| Crystal habit | Euhedral crystals with hemihedral morphology |
| Twinning | Present |
| Mohs scale hardness | 3 |
| Luster | Vitreous |
| Streak | Saffron-yellow |
| Diaphaneity | Translucent to transparent |
| Specific gravity | 6.42 |
| Optical properties | Biaxial (+) |
| Refractive index | nα = 2.105 nβ = 2.320 nγ = 2.650 |
| Birefringence | δ = 0.545 |
| Pleochroism | Feeble, yellow to orange |
| 2V angle | 88° (measured) |
| References | [2][3][4][5][6] |
Hemihedrite is a rare lead zinc chromate silicate mineral with formula Pb10Zn(CrO4)6(SiO4)2(F,OH)2. It forms a series with the copper analogue iranite.[3]
- ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
- ^ Handbook of Mineralogy
- ^ a b Hemihedrite on Mindat.org
- ^ Hemihedrite data on Webmineral
- ^ Mineralienatlas
- ^ McLean, W.J.; Anthony, J.W. (1970). "The crystal structure of hemihedrite". American Mineralogist. 55: 1103–1114.