Dolomite

Dolomite is really a mineral that is common but rarely clean adequate for faceting. A collector that is an uncommon gem with distinctive birefringence. Dolomite is really a sedimentary that is common mineral and can be seen around the world in massive beds several hundred feet thick. Crystals are somewhat unusual and are usually found as Druzes or clusters of small rhombohedral crystals with colorless, tan or colors which are pink. Large, clean, facetable crystals can be rare. Dolomite is chemically just like Calcite. Dolomite contains magnesium, Calcite does not.

 

Category: Carbonate minerals
Chemical Formula: CaMg(CO3)2
Crystallography: Trigonal – Rhombohedral
Crystal Habit: Crystals typically tabular, many minor forms, may exhibit curved faces, to 20 cm; saddle-shaped aggregates, columnar, stalactitic, granular, massive.
Twinning: Common as simple contact twins and in combinations; also lamellar.

 

Cleavage: [1011] Perfect, [1011] Perfect, [1011] Perfect (rhombohedral)
Fracture: Subconchoidal
Tenacity: Brittle
Hardness (Mohs): 3.5 – 4.0
Density: 2.84 – 2.86 (g/cm3)
Luminescence: May be Triboluminescent
Radioactivity: Not Radioactive

 

Color: Colorless, White, Grey, Yellow, Brown, Pale Pink
Transparency: Transparent, Translucent
Luster: Vitreous, Pearly
Refractive Index: 1.679 – 1.703  Uniaxial ( – )  (may be anomalously Biaxial)
Birefringence: 0.1790 – 0.1810
Dispersion: Very Strong
Pleochroism: None