Mineral Type - Calcite
A very common and widespread mineral with highly variable forms and colours. Calcite is best recognized by its relatively low Mohs hardness (3) and its high reactivity with even weak acids, such as vinegar, plus its prominent cleavage in most varieties.
Transparency: 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)
Elements listed: C, Ca, O
Common Impurities: Mn,Fe,Zn,Co,Ba,Sr,Pb,Mg,Cu,Al,Ni,V,Cr,Mo
Class (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)
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)