Artinite

Artinite is a hydrated magnesium carbonate mineral with formula: Mg2(CO3)(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.

Artinite
Artinite from New Idria District, California
General
CategoryCarbonate mineral
Formula
(repeating unit)
Mg2(OH)2CO3·3H2O
Strunz classification5.DA.10
Crystal systemMonoclinic
Crystal classPrismatic (2/m)
(same H-M symbol)
Space groupC2/m
Unit cella = 16.56, b = 3.15
c = 6.22 [Å]; β = 99.15°; Z = 2
Identification
ColorWhite
Crystal habitAcicular crystals, fibrous veinlets, botryoidal crusts, and spherical aggregates
CleavageOn {100} perfect; on {001} good.
Mohs scale hardness2.5
LusterVitreous, silky
StreakWhite
DiaphaneityTransparent
Specific gravity2.01 - 2.03
Optical propertiesBiaxial (-)
Refractive indexnα = 1.488 - 1.489 nβ = 1.533 - 1.534 nγ = 1.556 - 1.557
Birefringenceδ = 0.068
References[1][2][3]

It occurs in low-temperature hydrothermal veins and in serpentinized ultramafic rocks. Associated minerals include brucite, hydromagnesite, pyroaurite, chrysotile, aragonite, calcite, dolomite and magnesite.[1]

It was first reported in 1902 in Lombardy, Italy. It was named for Italian mineralogist, Ettore Artini (1866–1928).[2]

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.

References

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