Jasper
Quartz var. Jasper (Microcrystalline Quartz) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal/Hexagonal; microcrystalline (cryptocrystalline) aggregate with no visible crystal faces
Mineral Group
Silicates (Tectosilicate subgroup)
Chemical Formula
SiO2 (Silicon Dioxide) with impurities of Fe2O3 (Iron Oxide Oxide)
Formation Process
Forms through the deposition of silica-rich fluids in volcanic ash or sedimentary beds (diagenetic), often replacing organic material or filling cavities.
About This Crystal
An opaque, impure variety of silica. This specimen shows a dull to waxy luster with a mottled reddish-brown and grey color palette. It has a dense, fine-grained texture lacking visible crystals.
Physical Characteristics
Color: Red, brown, yellow, and grey; Streak: White; Cleavage: None; Fracture: Conchoidal to splintery; Specific Gravity: 2.58–2.91; Fluorescence: Usually none; Tenacity: Brittle but tough.
Optical Properties
Refractive Index: 1.54–1.55; Birefringence: None (isotropic aggregate); Pleochroism: None; Transparency: Completely opaque even on thin edges.
Hardness & Durability
Origin Region
Globally distributed; notable sources in India, Russia, Brazil, USA (Oregon, Idaho), and Australia. Found in sedimentary or volcanic environments.
Hardness & Durability
Mohs Hardness: 6.5–7.0; Excellent toughness due to microcrystalline structure with no cleavage; highly durable for jewelry and carvings.
Care & Maintenance
Safe to clean with warm soapy water or ultrasonic cleaners. Generally resistant to household chemicals, but avoid extreme heat which may cause color shifts in iron-rich zones.
Rarity & Value
Common; value is determined by color patterns and polish quality. Raw specimens like this are inexpensive, often sold by weight for lapidary use.
Special Characteristics
Known for its 'painterly' patterns caused by diffusion of iron and manganese during formation. It is completely opaque, distinguishing it from translucent chalcedony or agate.
Lore & History
Historically used for seals, amulets, and architectural ornamentation in ancient Egypt and Mesopotamia. Traditionally known as the 'Supreme Nurturer' in folklore, associated with grounding and protection.