Calcite
Calcite (Calcium Carbonate) · Mineral Specimen / Industrial Mineral
Crystal System
Trigonal; commonly occurs in rhombohedral, scalenohedral, or massive habits. This specimen appears as a rough, crystalline fragment.
Mineral Group
Carbonates (Calcite subgroup)
Chemical Formula
CaCO3 (with possible traces of Fe, Mg, or Mn influencing color)
Formation Process
Sedimentary precipitation in marine environments, or hydrothermal deposition in veins. Can also form through metamorphic processes in marble.
About This Crystal
A translucent to opaque rough fragment with a pale yellowish to off-white body color. It displays a vitreous to waxy luster and a sugary to crystalline texture on fractured surfaces.
Physical Characteristics
Color: pale yellow/cream; Streak: white; Cleavage: Perfect rhombohedral in three directions; Fracture: Conchoidal to uneven; Specific Gravity: 2.71; Fluorescence: Often fluoresces red, blue, or yellow under UV light.
Optical Properties
Refractive Index: 1.486–1.658; Birefringence: Extremely high (0.172), known for double refraction; Uniaxial negative.
Hardness & Durability
Origin Region
Globally abundant; notable sources include Mexico, Iceland, and the United Kingdom. Often found in sedimentary limestone and marble environments.
Hardness & Durability
Mohs Hardness: 3 (soft); Toughness: Poor; very brittle and sensitive to pressure and scratching.
Care & Maintenance
Clean only with warm soapy water. Avoid all acids (including vinegar) as they will dissolve the stone. Store separately to prevent scratches from harder minerals.
Rarity & Value
Common; very affordable. Value is determined by clarity, color saturation, and the presence of well-defined crystal faces.
Special Characteristics
Strong acid reaction (effervescence), high double refraction (birefringence), and common thermoluminescence or fluorescence.
Lore & History
Historically used in optics (Iceland Spar) for polarizing light. Metaphysically associated with the Solar Plexus chakra and believed to be a powerful cleanser and amplifier of energy.