Skorpionite

Skorpionite
240px Skorpionite
General
Category	Phosphate mineral
Formula (repeating unit)	Ca3Zn2(PO4)2CO3(OH)2·H2O
Strunz classification	8.DO.45
Dana classification	43.5.20.
Crystal symmetry	Monoclinic - prismatic H-M symbol (2/m) Space group: B2/b
Unit cell	a = 19.042 Å, b = 9.309 Å c = 6.519 Å; β = 92.72°; Z = 4
Identification
Color	colorless
Crystal habit	needle-like crystals elongated parallel to [001]; bladed, sword-shaped
Crystal system	Monoclinic
Fracture	irregullar/ uneven
Tenacity	brittle
Mohs scale hardness	3½
Luster	vitreous
Streak	white
Diaphaneity	transparent
Density	3.15 g/cm3
Optical properties	Biaxial (-)
Refractive index	nα = 1.588 nβ = 1.645 nγ = 1.646
Birefringence	δ = 0.057
2V angle	15.0° (measured)
References

Skorpionite (IMA2005-010) is a zinc phosphate mineral with chemical formula Ca₃Zn₂(PO₄)₂CO₃(OH)₂·H₂O, originally found in the Skorpion Mine and named after it (Rosh Pinah, Lüderitz district, ǁKaras Region, Namibia).