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Hematite | Blog

Formula Fe2O3
Molecular mass 159.69 g/mol
IMA Status Valid
Systematics according to IMA (Mills et al., 2009)
Class Oxides and hydroxides
Group corundum
Physical properties
Color Reddish brown to iron black
Dash color Red-brown
Shine Metallic, brushed
Transparency Transparent in thin sheets
Mohs hardness 5.5—6.5
fragility Fragile
Cleavage Missing
kink semi-conchoidal
Density 4.9—5.3 g/cm³
Crystallographic properties
space group R3c (R3 2/c)
Syngony Trigonal
Optical properties
optical type uniaxial
Refractive index nα = 3.150–3.220, nβ = 2.870–2.940
Birefringence 0.28
optical relief Short
Dispersion of optical axes Missing
Pleochroism Weak
Luminescence Missing

Varieties of hematite

Many of the various forms of hematite have separate names. The steel-gray crystals and coarse-grained varieties have a lustrous metallic sheen and are known as mirror iron ore; thin scaly types are called micaceous hematite. Much hematite occurs in a soft, fine-grained, earthy form called red ocher. Intermediate between these types are compact varieties, often with a kidney-like surface (bud ore) or a fibrous structure (pencil ore). Red ocher is used as a coloring pigment; used for polishing sheet glass.

Strode Anna

Anna Strod – director of the jewelry online store Author and editor of the jewelry blog

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