Class: Carbonates (Nitrates)
Group: Calcite
Original description: ‘Magnesit’ Karsten, D. L. G., 1808. Erd-und steinarten. Magnesit — Mineralogische Tabellen, Berlin: 48 [
view in ‘Library’].
Type locality: Bettolino, Baldissero Canavese, Province of Turin, Piedmont Region, Italy.
Type material: unknown.
Etymology: for the magnesium in its composition.
Distribution: some well-studied localites include: Austria: Styria; Brazil: Bahia, Brumado; China: Liáoníng; Greece: Magnesia; Italy: Piedmont, Baldissero Canavese; USA: California (
Anthony et al., 2001—2005).
Chemistry
MgCO3
Essential elements: carbon (C), oxygen (O), magnesium (Mg).
Crystal data
Crystallography: trigonal — hexagonal scalenohedral.
Crystal habit: uncommon as crystals, to 30 cm, with large {1011} or {0112}, modified by {1010}, {1120}, or tabular on {0001}; typically earthy, fibrous, granular, massive (
Anthony et al., 2001—2005).
Optical properties
Colour: colourless, white, pale yellow, pale brown, faintly pink, lilac-rose; colourless in transmitted light (
Anthony et al., 2001—2005).
Diaphaneity: transparent to translucent (
Anthony et al., 2001—2005).
Lustre: vitreous (
Anthony et al., 2001—2005).
Refractive index: 1.509—1.72 — anisotropic [uniaxial (-)] (
Lazzarelli, 2012).
Birefringence: 0.19—0.202.
Dispersion: very strong (
Anthony et al., 2001—2005).
Pleochroism: none.
Material from ‘Repository’