Smoky Quartz
Quartz var. Smoky Quartz · Semi-Precious Gemstone / Mineral Specimen
Crystal System
Trigonal; typically prismatic with hexagonal cross-sections and pyramidal terminations
Mineral Group
Silicates; Tectosilicate (Framework Silicate)
Chemical Formula
SiO2 (Silicon Dioxide with trace aluminum and natural irradiation)
Formation Process
Forms in igneous and metamorphic environments, specifically pegmatites and hydrothermal veins, where natural radiation from surrounding rock colors the silicon dioxide
About This Crystal
A translucent to transparent variety of quartz ranging from pale grayish-brown to nearly black (morion). This specimen shows a vitreous luster with uneven, conchoidal fracture surfaces
Physical Characteristics
Color: Brownish-gray; Streak: White; Cleavage: None (poor); Fracture: Conchoidal; Specific Gravity: 2.65; Fluorescence: Usually inert; Tenacity: Brittle
Optical Properties
Refractive Index: 1.544-1.553; Birefringence: 0.009; Pleochroism: Weak to moderate in darker stones; Diaphaneity: Transparent to translucent
Hardness & Durability
Origin Region
Notable sources include Brazil, Switzerland (Swiss Alps), Madagascar, and the United States (notably Pikes Peak, Colorado)
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; Stability: Stable to light but can lose color if heated to extremely high temperatures (approx 200-300°C)
Care & Maintenance
Clean with warm soapy water and a soft brush; avoid steam cleaners and ultrasonic cleaners if the stone has internal inclusions; store away from harder stones like topaz or sapphire
Rarity & Value
Common and abundant; value is determined by clarity and size; larger, well-formed crystals from famous localities are prized by collectors; often heat-treated to create Citrine
Special Characteristics
Color results from free silicon formed from silicon dioxide by natural irradiation of aluminum-containing quartz; may exhibit internal veil-like inclusions
Lore & History
Historically used in Scotland as 'Cairngorm' for jewelry and weapon handles; traditionally associated with grounding, protection, and the root chakra in modern crystal healing lore