Yellow Calcite
Calcite var. Yellow (IMA: Calcite) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; commonly found in massive or rhombohedral habits
Mineral Group
Carbonate (Calcite Group)
Chemical Formula
CaCO3 (Calcium Carbonate with trace Iron/Sulfur)
Formation Process
Sedimentary precipitation or Hydrothermal deposition in low-temperature vein systems
About This Crystal
A translucent to opaque specimen with a buttery yellow to honey-orange hue. It possesses a characteristic waxy to vitreous luster and a smooth, almost 'soapy' surface texture when tumbled.
Physical Characteristics
Color: Yellow; Streak: White; Cleavage: Perfect rhombohedral in 3 directions; Fracture: Uneven; Specific Gravity: 2.71; Fluorescence: Often pink or orange under UV light.
Optical Properties
Refractive Index: 1.486–1.658; Birefringence: Extremely high (0.172); Optically Uniaxial (-); No significant pleochroism.
Hardness & Durability
Origin Region
Mexico (Zacatecas), Brazil, and USA; formed in sedimentary limestone or hydrothermal environments
Hardness & Durability
Mohs Hardness: 3; very soft and brittle; unsuitable for rings but used in pendants; easily scratched by steel or glass.
Care & Maintenance
Avoid all acids (vinegar/lemon juice) as it will dissolve; clean only with warm soapy water; store separately to avoid scratches from harder stones.
Rarity & Value
Common; Value is generally low, based on color intensity and size; typically natural with no common treatments.
Special Characteristics
Strong double refraction (birefringence) is its most famous property; can exhibit 'acid-washed' surfaces for a smoother feel.
Lore & History
Historically used in mortars and building materials. In metaphysical traditions, it is associated with the Solar Plexus chakra, believed to boost self-confidence and mental clarity.