Granite
Plutonic Igneous Rock (composed primarily of Quartz, Feldspar, and Mica) · Dimension Stone and Architectural Material
Crystal System
Multisystem aggregate (composed of minerals crystallizing in hexagonal, monoclinic, and triclinic systems)
Mineral Group
Silicates (Composite Igneous Rock)
Chemical Formula
Complex silicate mixture including SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8, and various micas/amphiboles
Formation Process
Igneous intrusive process resulting from the slow crystallization of magma below the Earth's surface under high pressure
About This Crystal
A coarse-grained intrusive igneous rock displaying a phaneritic texture with interlocking crystals of translucent grey quartz, white to pink feldspar, and dark flakes of biotite mica, polished flat as a monumental marker
Physical Characteristics
Grey and black speckled body color, white streak, uneven fracture, specific gravity around 2.65 to 2.75, brittle tenacity, excellent durability against weathering
Optical Properties
Aggregate optical properties depending on constituent minerals; quartz component shows uniaxial positive optics and double refraction under microscopic examination
Hardness & Durability
Origin Region
Widely distributed globally in continental shields, mountain cores, and intrusive plutons worldwide
Hardness & Durability
Mohs hardness of 6 to 7 based on constituent quartz and feldspar minerals, highly resistant to scratching, weathering, and environmental degradation
Care & Maintenance
Requires minimal maintenance, cleaning with mild soap and water, highly resistant to chemical erosion and thermal shock in outdoor environments
Rarity & Value
Extremely common globally, value is determined entirely by architectural processing, monumental engraving, and aesthetic stone selection rather than mineral rarity
Special Characteristics
Displays a classic salt-and-pepper or flecked appearance due to the random distribution of dark biotite and amphibole crystals within light-colored quartz and feldspar matrices
Lore & History
Historically utilized extensively by ancient civilizations including the Ancient Egyptians for obelisks, pillars, and monumental architecture due to its exceptional strength and longevity