Chemistry:Artinite

Short description: Hydrated basic magnesium carbonate mineral

Artinite
Artinite from New Idria District, California
General
Category	Carbonate mineral
Formula (repeating unit)	Mg 2(CO 3)(OH) 2 · 3H2O
Strunz classification	5.DA.10
Crystal system	Monoclinic
Crystal class	Prismatic (2/m) (same H-M symbol)
Space group	C2/m
Unit cell	a = 16.56, b = 3.15 c = 6.22 [Å]; β = 99.15°; Z = 2
Identification
Color	White
Crystal habit	Acicular crystals, fibrous veinlets, botryoidal crusts, and spherical aggregates
Cleavage	On {100} perfect; on {001} good.
Mohs scale hardness	2.5
|re|er}}	Vitreous, silky
Streak	White
Diaphaneity	Transparent
Specific gravity	2.01 – 2.03
Optical properties	Biaxial (−)
Refractive index	nα = 1.488 – 1.489 nβ = 1.533 – 1.534 nγ = 1.556 – 1.557
Birefringence	δ = 0.068
References

Artinite is a hydrated basic magnesium carbonate mineral with formula: Mg
2(CO
3)(OH)
2 · 3H₂O. It forms white silky monoclinic prismatic crystals that are often in radial arrays or encrustations. It has a Mohs hardness of 2.5 and a specific gravity of 2.

It occurs in low-temperature hydrothermal veins and in serpentinized ultramafic rocks. Associated minerals include brucite, hydromagnesite, pyroaurite, chrysotile, aragonite, calcite, dolomite and magnesite.

It was first reported in 1902 in Lombardy, Italy. It was named for Italian mineralogist, Ettore Artini (1866–1928).

Artinite sometimes forms balls of radiating, fibrous crystals. Specimen from New Idria district, California US. Size: 9.2 x 5.2 x 1.5 cm.