Iranite

For the fossil cephalopod "Iranites", see Xenodiscidae.

Iranite
General
Category	Silicate mineral
Formula (repeating unit)	Pb10Cu(CrO4)6(SiO4)2(F,OH)2
IMA symbol	Irn[1]
Strunz classification	7.FC.15
Crystal system	Triclinic
Space group	Triclinic pedial H-M symbol: (1) Space group: P1
Unit cell	a = 10.02 Å, b = 9.54 Å, c = 9.89 Å; α = 104.5°, β = 66°, γ = 108.5°; Z = 1
Identification
Color	Brown to orange
Crystal habit	Equant to flattened euhedral crystals
Mohs scale hardness	3
Luster	Vitreous
Streak	Yellow
Specific gravity	5.8
Optical properties	Biaxial
Refractive index	nα = 2.250 – 2.300 nγ = 2.400 – 2.500
Birefringence	δ = 0.150 – 0.200
References	[2][3][4]

Iranite (Persian: ایرانیت) is a triclinic lead copper chromate silicate mineral with formula Pb₁₀Cu(CrO₄)₆(SiO₄)₂(F,OH)₂. It was first described from an occurrence in Iran. It is the copper analogue of hemihedrite (Pb₁₀Zn(CrO₄)₆(SiO₄)₂(F,OH)₂).[3]

It occurs as an oxidation product of hydrothermal lead-bearing veins. Associated minerals include dioptase, fornacite, wulfenite, mimetite, cerussite and diaboleite.[2] It was first described in 1970 for an occurrence in the Sebarz Mine, northeast of Anarak, Iran.[3][2]

References

1. 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.
2. Handbook of Mineralogy
3. Mindat page for Iranite
4. Webmineral data for Iranite