Apache Tear
Obsidian (Volcanic Glass) · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Amorphous (No crystal system; non-crystalline volcanic glass)
Mineral Group
Silicates (Extrusive Igneous Rock / Mineraloid)
Chemical Formula
SiO2 (70-75%) + MgO, Fe3O4 (varies based on impurities)
Formation Process
Igneous; formed by the rapid cooling of high-silica rhyolitic lava which prevents crystallization, resulting in a glass. These specific nodules form within perlite layers.
About This Crystal
A rounded, sub-spherical nodule of obsidian. It appears black and opaque in thick sections but reveals translucent smoky brown or grey when held to light. Typical vitreous to sub-vitreous luster with a smooth, glass-like surface when polished or chipped.
Physical Characteristics
Color: Jet black to smoky brown. Streak: White. Cleavage: None. Fracture: Conchoidal (shell-like curves). Specific Gravity: 2.35-2.60. Luster: Vitreous. Transparency: Translucent to opaque.
Optical Properties
Refractive Index: 1.48-1.51 (Singly refractive). No birefringence, pleochroism, or dispersion. Lacks internal crystalline structure to create fire.
Hardness & Durability
Origin Region
Notable in Arizona and Nevada, USA; specifically Superior, Arizona. Found in areas of high silica volcanic activity.
Hardness & Durability
Mohs Hardness: 5.0-5.5. Brittle tenacity makes it susceptible to chipping or scratching compared to quartz. Suitable for jewelry with protective settings.
Care & Maintenance
Clean with warm soapy water and a soft brush. Avoid ultrasonic cleaners and steam cleaning due to thermal shock risk. Store separately to prevent scratches from harder stones like quartz.
Rarity & Value
Common and widely available. Value is determined by size, translucency, and the smoothness of the surface. Generally inexpensive, ranging from $1 to $20 depending on size and polish.
Special Characteristics
Exhibits transparency when back-lit despite appearing jet black. Known for its perfectly conchoidal fracture which was historically used for sharp tools.
Lore & History
Named after a legend involving the Apache tribe in Arizona during the 1870s; it is said that the stones are the frozen tears of women mourning warriors who leaped from a cliff to avoid capture. Traditionally used for grounding and protection from grief.