Garnierite
Rock made of serpentine, talc, chlorite
Uncommon · (Ni,Mg)₃Si₂O₅(OH)₄ to (Ni,Mg)₃Si₄O₁₀(OH)₂ (variable)
Not a valid mineral name but a field name for the green nickel ore that fills veins and pockets in weathered, serpentinised ultramafic rocks: an intimate mixture of nickel-bearing serpentine, talc, sepiolite, smectite or chlorite, the green darkening with the nickel. An important nickel ore of laterite deposits, named in 1874 for Jules Garnier, who had announced nickel in New Caledonia in 1867.
Rock
- Kind of rock
- Chemical sedimentary rock
- Rock family
- Ultramafic rock (peridotite, serpentinite)
- Deposits
- Lateritic deposit
- Metals
- Nickel
- How it forms
- Nickel leached from weathering serpentinised ultramafic rock gathers in veins and pockets of the laterite.
- Uses
- Ore of nickel, mined in New Caledonia from the end of the nineteenth century.
Identity
- Formula
- (Ni,Mg)₃Si₂O₅(OH)₄ to (Ni,Mg)₃Si₄O₁₀(OH)₂ (variable)
- Chemical class
- Silicate
- Ore of
- Nickel
Crystallography
- Crystal system
- Amorphous
- Habits
- Massive, Earthy, Botryoidal
- Fracture
- Uneven
Physical properties
- Mohs hardness
- 2.5
- Density
- 2.7 g/cm³
- Luster
- Earthy, Waxy, Dull
- Colors
- green, yellow-green, dark green, emerald green
- Transparency
- Opaque, Translucent
Geology
- Origins
- Sedimentary
- Host rocks
- Ultramafic rock (peridotite, serpentinite)
- Associated minerals
- Serpentine, Talc, Chlorite, Goethite, Quartz
- Geography
- New Caledonia, Dominican Republic (Falcondo), USA (Riddle, Oregon), Russia (Ural Mountains)
Classification
- Rarity
- Uncommon
- Gem quality
- No
Sources
- Garnierite. Wikipedia.
- Laterite. Wikipedia.
- C. R. Hallsworth, R. W. O’B. Knox, BGS Rock Classification Scheme, Volume 3: Classification of sediments and sedimentary rocks (Research Report RR 99-03). British Geological Survey, 1999.
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