Smoky Quartz in Matrix
Quartz variety Smoky Quartz · Mineral Specimen / Semi-Precious Gemstone
Crystal System
Trigonal; commonly occurs as hexagonal prisms with pyramidal terminations or as massive druses within cavities.
Mineral Group
Silicates (Tectosilicates)
Chemical Formula
SiO2 with aluminum impurities and natural irradiation
Formation Process
Magmatic or hydrothermal; primarily forms in igneous rocks like granite or pegmatites where natural radiation from surrounding rock influences the crystal color.
About This Crystal
This specimen features translucent to opaque dark brown or 'smoky' crystals embedded within a coarse, rocky matrix. The crystals exhibit a vitreous luster and appear as small, irregular druzy grains or small points within a vug or pocket.
Physical Characteristics
Color: Brown to black; Streak: White; Fracture: Conchoidal; Specific Gravity: 2.65; Lustre: Vitreous; Diaphaneity: Translucent to opaque.
Optical Properties
Uniaxial positive; Refractive Index: 1.544-1.553; Birefringence: 0.009; No significant pleochroism in lighter specimens.
Hardness & Durability
Origin Region
Found globally, with notable deposits in the Swiss Alps, Brazil, Madagascar, and various granite-rich regions of the USA (e.g., Colorado).
Hardness & Durability
Mohs Hardness: 7; Toughness: Good; very durable for most jewelry and handling, though the matrix may be crumbly depending on rock type.
Care & Maintenance
Clean with warm soapy water and a soft brush. While stable, prolonged exposure to extreme heat or intense UV light can potentially cause color fading over many years.
Rarity & Value
Common; value is determined by the size and clarity of the crystals and the aesthetic appeal of the matrix. Generally affordable for collectors.
Special Characteristics
Natural irradiation of aluminum trace elements produces the distinctive smoky color. Can exhibit piezoelectricity.
Lore & History
Historically used in Scotland as 'Cairngorm' for highland dress ornaments. In metaphysical traditions, it is considered a grounding stone associated with the Root Chakra and protection.