|Mineral class||Carbonates : Calcite group.|
|Habitus|| Calcite is the mineral that shows the most various
types of crystals. In my mind is the number of 137 different crystal forms, but I'm
not shure about it. Anyone who knows?|
Most common forms are tabular, sharp and stubby rhomboedric, prismatic an scalenoedric (dogtooth spar).
Calcite also occur as fibric aggregates, as coarse to fine grained aggregates or stalactitic.
|Cleavage||Perfect rhomboedric in three planes, subconchoidal fracture.|
|Color||usually colorless, but nuances in blue, yellow, green, red, violet, even black and opaque.|
|Streak||White to grayish.|
|Luster||Vitreous to pearly or dull.|
|Occurance||Calcite is the main ingredience of limestone rocks. It is also the mineral that builds up stalagmites in caves. Calcite is also a common mineral in hytdrothermal veins. Calcite can also occur in some eruptive rocks (Alnö), but only in the depth, since it is not stable at athmospheric pressure as a melt.|
|Notes|| Reacts violently with hydrochloric acid.|
Double refractive. Clear calcite is called Iceland spar, since it was mined there.
Often flourescent, especially when contaminated by manganeese.
|Locations|| A very common mineral |
| To carbonates index.
|| Mineral group index.
If you have some questions, suggestions or comments you are welcome to write me a line or two.