Yellow Calcite
Calcite (var. Yellow) · Decorative Stone / Semi-Precious Mineral
Crystal System
Trigonal crystal system; typically found in massive or rhombohedral habits in nature, though this specimen is carved into a decorative shape.
Mineral Group
Carbonates
Chemical Formula
CaCO3 (Calcium Carbonate) with trace amounts of iron or sulfur impurities causing yellow coloration
Formation Process
Primarily Sedimentary (chemical precipitation from calcium-rich solutions) or Metamorphic; can also form under hydrothermal conditions.
About This Crystal
A vibrant yellow, translucent to nearly opaque specimen with a waxy to vitreous luster. This specific piece has been carved and polished into a duck shape, masking its natural rhombohedral cleavage.
Physical Characteristics
Color: Bright lemon yellow to golden yellow; Streak: White; Cleavage: Perfect rhombohedral in raw form; Fracture: Conchoidal; Specific Gravity: 2.71; Fluorescence: Often glows pink or orange under UV light.
Optical Properties
Refractive Index: 1.486 - 1.658; Birefringence: Extremely high (0.172); Uniaxial negative; Lacks significant pleochroism in yellow varieties.
Hardness & Durability
Origin Region
Major sources include Mexico, Brazil, USA, and Belgium. Often found in large sedimentary deposits or hydrothermal veins.
Hardness & Durability
Mohs Hardness: 3 (soft); Toughness: Poor; very brittle and sensitive to pressure. Not suitable for rings but popular for carvings and tumbled stones.
Care & Maintenance
Avoid acids (even vinegar) which causes effervescence; clean only with warm soapy water and a soft cloth. Store separately as it is easily scratched by harder minerals like quartz.
Rarity & Value
Very Common; generally inexpensive. Value is determined by color intensity, clarity, and the quality of the lapidary work (carving).
Special Characteristics
Known for intense double refraction in clear specimens (Iceland Spar). In this yellow form, it is prized for its 'honey-like' depth and potential for UV fluorescence.
Lore & History
Historically used in limestone and marble forms since antiquity. Metaphysically associated with the Solar Plexus chakra, believed to enhance self-confidence, hope, and mental clarity.