Chrysoprase
Quartz var. Chrysoprase (Microcrystalline Quartz) · Semi-Precious Gemstone / Collector Mineral
Crystal System
Trigonal (Hexagonal system); typically occurs in cryptocrystalline or microcrystalline aggregates (massive habit) rather than distinct crystals.
Mineral Group
Silicates (Subgroup: Tectosilicates / Chalcedony variety)
Chemical Formula
SiO2 (Silicon Dioxide) with Nickel (Ni) inclusions
Formation Process
Secondary process resulting from the deep weathering or lateritization of nickeliferous serpentinites or other ultramafic rocks in warm climates.
About This Crystal
Apple-green to deep forest-green gemstone with a waxy to vitreous luster. It is typically translucent to nearly opaque. This specimen shows a tumbled, irregular shape with consistent apple-green coloring and slight brownish-yellow matrix or inclusion on the corner.
Physical Characteristics
Color: Apple-green; Streak: White; Cleavage: None; Fracture: Conchoidal to splintery; Specific Gravity: 2.58–2.64; Fluorescence: Generally inert, but may show weak green under LWUV.
Optical Properties
Refractive Index: 1.530–1.544; Birefringence: Up to 0.004; Pleochroism: None; Optical Character: Aggregate (Aggr); typically lacks specific optical phenomena like asterism.
Hardness & Durability
Origin Region
Western Australia (most famous), Poland, Germany, Russia, Brazil, and Arizona, USA. It forms in nickel-rich weathered serpentinites.
Hardness & Durability
Mohs Hardness: 6.5–7. Toughness is good due to its microcrystalline structure. Stable under normal conditions, but can be sensitive to prolonged heat.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic and steam cleaners. Store away from direct, prolonged sunlight to prevent potential dehydration-related fading. Keep separate from harder gems like Topaz or Sapphire.
Rarity & Value
Uncommon; it is the most valuable variety of chalcedony. Value is driven by the intensity and uniformity of the apple-green color and degree of translucency. High-quality Australian specimens are most prized.
Special Characteristics
Color is derived from nickel silicate inclusions (e.g., kerolite or pimelite) rather than chromium. It can feature dendritic inclusions or 'gasht' (vein-like) patterns in raw specimens.
Lore & History
Ancient Greeks, Romans, and Egyptians used it for seals and jewelry. Traditionally associated with the Heart Chakra, it is historically believed to promote optimism, joy, and emotional balance. Alexander the Great was rumored to carry a piece for protection.