Aragonite group Flashcards
CaCO3
Aragonite
What are the three common habits of aragonite?
- acicular pyramidal usually in radiating groups of crystals
- tabular with prominent vertical pinacoid and prisms
- cyclic hexagonal-like twins with a basal plane
Has a distinct pinacoidal and the prismatic is poor.
Has a distinct pinacoidal and the prismatic is poor.
Aragonite
Aragonite has a hardnes of _____
3.5 - 4
It has a specific gravity of 2.94
Aragonite
What are the usual color of aragonite ?
Colorless, white, pale yellow, and variously tinted. Luster vitreous. Transparent to translucent.
Deposited from hot springs, and associated with gypsum. As fibrous crusts on serpentine and in amygdaloidal cavities in basalt. In metamorphic assemblages of the blueschist facies, as a result of crystallization at high pressure but relatively low temperature.
Aragonite
BaCO3
Witherite
Orthorhombic, with crystals always twinned on {110} forming pseudohexagonal dipyramids by the intergrowth of three individuals.
Witherite
In hydrothermal veins associated with galena.
Witherite
The hardness of witherite
3.5
It has a specific gravity of 4.3
Witherite
SrCO3
Strontianite
Orthorhombic, usually in radiating clusters of acicular crystals (like type 1 of aragonite). Commonly twinned on {110} giving a pseudohexagonal appearance.
Strontianite
It has a prismatic good cleavage
Strontianite
Strontianite has a hardness of _______.
3.5 - 4
It has a specific gravity of 3.7
Strontianite
Common color of strontianite
White, gray, yellow, green.
Occurs in low-temperature hydrothermal veins and deposits associated with barite, celestite, and calcite. Also present in sulfide veins, and a rare constituent of igneous rocks.
Strontianite
PbCO3
Cerussite
Orthorhombic crystals commonly with varied habit and many forms. Often tabular on {010}, and in reticulated groups of plates crossing each other at 60° angles.
Cerussite
Has a cleavage prismatic
Cerussite
Cerussite has a hardness of ______.
3 - 3.5
