Mineral Type - Calcite
Name
Ancient name. Named as a mineral by Gaius Plinius Secundus (Pliny the elder) in 79 from Calx, Latin for Lime.Physical Properties
Lustre: Vitreous, Sub-Vitreous, Resinous, Waxy, PearlyTransparency: Transparent, Translucent
Colour: White, Yellow, Red, Orange, Blue, Green, Brown, Gray etc
Streak: White
Hardness: 3 on Mohs scale
Tenacity: Brittle
Cleavage: Perfect. Perfect on {1011}
Parting: Readily along twin lamellae {0112} and {0001}
Fracture: Conchoidal
Density: 2.7102(2) g/cm3 (Measured) 2.711 g/cm3 (Calculated)
Chemical Properties
Formula: CaCO3Elements listed: C, Ca, O
Common Impurities: Mn,Fe,Zn,Co,Ba,Sr,Pb,Mg,Cu,Al,Ni,V,Cr,Mo
Crystallography
Crystal System: TrigonalClass (H–M): 3m (3 2/m) - Hexagonal Scalenohedral
Space Group: R3c
Morphology: Over 800 different forms have been described. Most commonly as acute rhombohedrons or prismatic with scalenohedral terminations, or combinations of the two
Twinning: At least four twin laws have been described, the most common being when the twin plane and the composition plane are {0112}. Also common with twinning on {0001} with {0001} as the compositional surface, producing re-entrant angles. Uncommon with {1011} or {0221} as twin planes, producing somewhat heart-shaped crystals ("butterfly" twins)