Siderite is a mineral that has another name - "iron spar". Contains up to 48% iron and is mined as iron ore. Mostly found as earthy masses, but also forms crystals. Cleavage is perfect. When heated above 300 degrees C. blackens and becomes highly magnetic.
You can see siderite stone for sale and buy it in the Minerals of Russia online store.
General | |
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Category | Carbonate mineral |
Formula (repeating unit) |
FeCO3 |
IMA symbol | Sd |
Strunz classification | 5.AB.05 |
Dana classification | 14.01.01.03 |
Crystal system | Trigonal |
Crystal class | Hexagonal scalenohedral (3m) H-M symbol: (3 2/m) |
Space group | R3c |
Unit cell | a = 4.6916, c = 15.3796 [Å]; Z = 6 |
Identification | |
Color | Pale yellow to tanish, grey, brown, green, red, black and sometimes nearly colorless |
Crystal habit | Tabular crystals, often curved - botryoidal to massive |
Twinning | Lamellar uncommon on{0112} |
Cleavage | Perfect on {0111} |
Fracture | Uneven to conchoidal |
Tenacity | Brittle |
Mohs scale hardness | 3.75 - 4.25 |
Luster | Vitreous, may be silky to pearly |
Streak | White |
Diaphaneity | Translucent to subtranslucent |
Specific gravity | 3.96 |
Optical properties | Uniaxial (-) |
Refractive index | nω = 1.875 nε = 1.633 |
Birefringence | δ = 0.242 |
Dispersion | Strong |