Onyx / Calcite Alabaster (commonly sold as White Onyx with a brown inclusion)
Calcite / Aragonite (Bandrd Calcite / Commercial 'Onyx') · Decorative Stone / Polished Mineral Specimen
Crystal System
Trigonal (Calcite) or Orthorhombic (Aragonite); carved into a polished egg shape
Mineral Group
Carbonates
Chemical Formula
CaCO3
Formation Process
Sedimentary and Hydrothermal; formed by the precipitation of calcium carbonate from mineral-rich waters in caves or thermal springs
About This Crystal
A smoothly polished, egg-shaped specimen of milky white to translucent pale greenish-white material, featuring a prominent, irregular, rich dark-brown to reddish-brown natural inclusion or patch of iron-rich mineral matrix on its surface.
Physical Characteristics
White to milky body color with a distinct brown patch; white streak; no cleavage visible due to polished egg form; conchoidal to uneven fracture; specific gravity around 2.71; brittle tenacity; effervesces in hydrochloric acid.
Optical Properties
Uniaxial negative with high birefringence; vitreous to waxy luster when polished; translucent to semi-opaque depending on thickness.
Hardness & Durability
Origin Region
Pakistan, Mexico, Egypt, and Iran; typically formed in limestone caves or hot springs
Hardness & Durability
Mohs hardness of 3; relatively soft and easily scratched by a knife or copper coin; low durability for daily-wear rings, suitable for display objects, carvings, and gentle handling.
Care & Maintenance
Clean with a soft, damp cloth and mild soap; avoid harsh chemical cleaners, acids, and vinegar which will etch the surface; do not soak in water; store away from harder stones to prevent scratching.
Rarity & Value
Common; widely available globally as decorative carvings, spheres, and eggs; inexpensive to moderately priced depending on the size and uniqueness of natural markings.
Special Characteristics
Features a striking contrasting natural matrix/inclusion spot against a uniform pale background, enhancing its visual appeal as a decorative piece.
Lore & History
Often associated with emotional balance, stress relief, and soothing energy in modern crystal healing practices. Historically, similar alabaster and cave calcite materials were used by ancient Egyptians and Greeks for carving vessels, jars, and decorative objects.