Calcite Mineral Specimen
Calcite · Mineral Specimen and Collector Mineral
Crystal System
Trigonal, with rhombohedral and massive crystal habits, often displaying fine-grained crystalline or scalenohedral forms on matrix.
Mineral Group
Carbonates (specifically anhydrous carbonates)
Chemical Formula
CaCO3
Formation Process
Hydrothermal and sedimentary processes, precipitating from calcium-rich aqueous solutions under varying temperature and pressure conditions, often filling vugs, veins, and limestone cavities.
About This Crystal
The specimen features a robust rock matrix heavily coated with sparkling, white to translucent micro-crystalline calcite aggregates. The central crust displays a vitreous to pearly luster with a sugary, granular texture, interspersed with earthy brown rock matrix and iron oxide staining along the crevasses.
Physical Characteristics
Color: White to colorless, with brownish matrix rock. Streak: White. Cleavage: Perfect rhombohedral in three directions at 75 degrees. Fracture: Conchohedral to uneven. Specific gravity: 2.71. Tenacity: Brittle. Fluorescence: Often exhibits strong pink, red, or white fluorescence under shortwave and longwave ultraviolet light.
Optical Properties
Refractive Index: 1.486 to 1.658. Strongly doubly refractive, exhibiting pronounced optical birefringence which causes clear double refraction of light passing through transparent cleavage pieces.
Hardness & Durability
Origin Region
Found worldwide; notable deposits in Mexico, USA (Missouri, Tennessee), Brazil, and China. Typically forms in sedimentary, metamorphic, and hydrothermal environments.
Hardness & Durability
Mohs hardness of 3, making it soft and easily scratched by a copper penny or steel knife. Low durability with perfect cleavage, making it unsuitable for everyday jewelry wear.
Care & Maintenance
Clean gently with a soft brush and warm soapy water. Avoid ultrasonic cleaners, steam cleaning, and acidic solutions (even mild acids like vinegar or lemon juice will etch and dissolve the calcium carbonate). Store separately to prevent scratching.
Rarity & Value
Common mineral globally, but aesthetic mineral specimens vary in price depending on crystal size, formation quality, and matrix preservation. Common and affordable as a raw specimen, with values increasing for exceptional crystal clarity or rare color forms.
Special Characteristics
Strong birefringence (double refraction), vigorous effervescence when exposed to dilute hydrochloric acid, and frequently strong fluorescence under UV light.
Lore & History
Historically used in optical devices during WWII (Iceland spar variety) for polarizing light. In metaphysical traditions, calcite is regarded as a powerful amplifier and cleanser of energy, traditionally associated with clearing negative energy and balancing the chakras.