Granite / Feldspar Matrix Rock
Plutonic Igneous Rock / Feldspar-rich Mineral Assemblage · Mineral Specimen / Rock
Crystal System
Varies by constituent minerals (Monoclinic and Triclinic for feldspars, Trigonal for quartz)
Mineral Group
Silicates (specifically Framework Silicates or Tectosilicates)
Chemical Formula
Complex silicate mixture containing KAlSi3O8 (Potassium feldspar), NaAlSi3O8 to CaAl2Si2O8 (Plagioclase), and SiO2 (Quartz)
Formation Process
Igneous formation through slow cooling of magma beneath the Earth's surface
About This Crystal
An opaque, coarse-grained rock matrix dominated by brownish-pink to tan feldspar crystals intergrown with translucent quartz and dark mineral flecks, showing a granular crystalline texture with vitreous to sub-vitreous luster on cleavage faces.
Physical Characteristics
Brownish-tan to reddish body color, white streak, uneven to sub-conchoidal fracture, specific gravity around 2.6 to 2.7, brittle tenacity, and no significant fluorescence
Optical Properties
Constituent minerals show varying refractive indices (around 1.52 to 1.55 for quartz and feldspar), doubly refractive with low birefringence
Hardness & Durability
Origin Region
Globally ubiquitous; common in continental crusts, mountain ranges, and pegmatite formations
Hardness & Durability
Mohs hardness typically around 6 to 7 for the aggregate matrix, moderate durability and resistance to wear, suitable for decorative stone and general handling
Care & Maintenance
Clean with warm soapy water and a soft brush, store away from abrasive materials, generally stable against normal light and household chemicals
Rarity & Value
Common, widely available globally as standard rock and mineral specimens with minimal commercial value outside of decorative or educational use
Special Characteristics
Contains sparkling cleavage faces of feldspar and embedded crystalline quartz grains reflecting light across the weathered matrix surface
Lore & History
Historically used as an architectural and monumental stone since ancient times. In metaphysical practices, it is often associated with grounding, stability, strength, and connection to the earth's foundational energy, though these are traditional beliefs rather than scientific claims.