Calcite (on matrix)
Calcite var. Honey Calcite · Mineral Specimen / Semi-Precious Stone
Crystal System
Trigonal; rhombohedral crystals often occurring in massive or crystalline aggregates
Mineral Group
Carbonates
Chemical Formula
CaCO3 with traces of Iron and Magnesium
Formation Process
Chemical precipitation from calcium-rich solutions in sedimentary environments or hydrothermal deposition in rock cavities.
About This Crystal
The specimen features an opaque to translucent yellowish-tan crystalline layer (honey calcite) attached to a dark, fine-grained grey host rock (matrix). The luster is vitreous to resinous on the crystals and dull on the matrix.
Physical Characteristics
Color: Honey yellow/tan; Streak: White; Cleavage: Perfect rhombohedral in three directions; Fracture: Conchoidal; Specific Gravity: 2.71; Fluorescence: Often fluoresces red or white under UV light; Effervesces in contact with dilute acids.
Optical Properties
Refractive Index: 1.486 - 1.658; Birefringence: Extremely high (0.172), often causing double refraction visibility; Uniaxial negative.
Hardness & Durability
Origin Region
Notable sources include Mexico (honey variety), USA (Missouri/Illinois), and Germany. Typically found in sedimentary limestone or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 3 (soft); Toughness: Poor due to perfect cleavage; Low durability, easily scratched by a copper penny or steel.
Care & Maintenance
Clean only with warm soapy water and a soft cloth. Avoid all acids (including vinegar), ultrasonic cleaners, and steam cleaners. Store separately from harder stones to prevent scratches.
Rarity & Value
Common; Value is generally low for small specimens, though high-clarity amber-colored rhombs or large clusters on matrix are preferred by collectors.
Special Characteristics
Strong double refraction (birefringence) in clear pieces; effervescence in acid; sensitive to pH changes.
Lore & History
Historically used as a flux in metal smelting and for making lime/cement. In metaphysical traditions, honey calcite is associated with the solar plexus and sacral chakras, believed to enhance willpower and motivation.