Non-silicate
Crystal system: trigonal (-)
Colour in hand specimen: white, often tinged with yellow or brown
Cleavage: rhombohedral
Hardness: 3.5-4
Colour in plane polarised light: colourless
Pleochroism: none
Relief: low
Birefringence: 0.179-(0.185); >4th order
Extinction: inclined
Twinning: lamellar, common
M543 Dolomite, associated with siderite and copper pyrites
Cerro Blanco, Chile
Rhombohedral crystals of dolomite with curved faces, associated with siderite (iron carbonate) and copper pyrite
White, slightly grey
Hardness 3.5 – 4
Non-silicate
Crystal system: trigonal (-)
Colour in hand specimen: white, often tinged with yellow or brown
Cleavage: rhombohedral
Hardness: 3.5-4
Colour in plane polarised light: colourless
Pleochroism: none
Relief: low
Birefringence: 0.179-(0.185); >4th order
Extinction: inclined
Twinning: lamellar, common
M543 Dolomite, associated with siderite and copper pyrites
Cerro Blanco, Chile
Rhombohedral crystals of dolomite with curved faces, associated with siderite (iron carbonate) and copper pyrite
White, slightly grey
Hardness 3.5 – 4