Green Onyx / Banded Calcite
Calcite var. Banded Calcite (commonly traded as Green Onyx) · Decorative Stone / Ornamental Mineral
Crystal System
Trigonal, massive or banded habit formed via chemical precipitation
Mineral Group
Carbonates
Chemical Formula
CaCO3
Formation Process
Sedimentary or hydrothermal precipitation of calcium carbonate from mineral-rich water in caves or hot springs, forming layers over time
About This Crystal
A polished, tumbled oval specimen with smooth surfaces, exhibiting translucent pale green to yellow-green tones and distinct parallel lighter banding stripes, typical of decorative banded calcite often commercially marketed as green onyx
Physical Characteristics
Light green and whitish body color, white streak, perfect rhombohedral cleavage (not visible in tumbled form), uneven to conchoidal fracture, specific gravity around 2.71, brittle tenacity, reacts with effervescence to dilute hydrochloric acid
Optical Properties
Uniaxial negative, strongly birefringent, shows double refraction, vitreous to waxy luster on polished surfaces
Hardness & Durability
Origin Region
Pakistan, Mexico, and Afghanistan; formed in limestone caves and hot spring deposits
Hardness & Durability
Mohs hardness of 3, making it soft and relatively easy to scratch with a knife or copper coin; poor durability for rings or high-wear jewelry due to softness and acid sensitivity
Care & Maintenance
Clean with a soft, damp cloth; avoid harsh chemical cleaners, acids, vinegar, and prolonged exposure to water or direct sunlight
Rarity & Value
Common, widely available and affordable, typically sold as polished pocket stones, carvings, or decorative spheres; usually untreated
Special Characteristics
Distinct parallel color banding, smooth tactile polish, and occasional weak white fluorescence under shortwave UV light
Lore & History
Popularly used in modern crystal healing for heart chakra alignment, emotional balance, and soothing stress, though these are traditional beliefs rather than scientific properties