Granite
Igneous Rock (Granitic composition) · Mineral Specimen / Igneous Rock
Crystal System
Multisystem aggregate (composed of minerals in the Trigonal, Monoclinic, and Triclinic systems with massive or granular habit)
Mineral Group
Silicates (Composite rock containing Tectosilicates and Phyllosilicates)
Chemical Formula
Complex silicate rock primarily composed of SiO2, KAlSi3O8, NaAlSi3O8, CaAl2Si2O8, and K(Mg,Fe)3AlSi3O10(OH)2
Formation Process
Igneous intrusive process involving the slow, deep-seated cooling and crystallization of silica-rich magma beneath the Earth's crust
About This Crystal
A coarse-grained intrusive igneous rock specimen showing a mottled appearance with white to translucent feldspar, clear quartz, and dark biotite or amphibole inclusions, displaying a crystalline granular texture and vitreous to sub-vitreous luster
Physical Characteristics
Colors include white, grey, pink, and black; white streak; uneven to conchoidal fracture; no single cleavage for the bulk rock (individual mineral components have distinct cleavage planes); specific gravity approximately 2.65 to 2.75; brittle tenacity
Optical Properties
Aggregate optical properties depending on constituent minerals; individual quartz grains show uniaxial positive optical character, while feldspars and micas show biaxial properties
Hardness & Durability
Origin Region
Worldwide, extensively found in continental shields, mountain cores, and major intrusive formations globally
Hardness & Durability
Mohs hardness ranges from 6 to 7 based on constituent quartz and feldspar; high durability and resistance to weathering, making it suitable for structural and decorative uses
Care & Maintenance
Clean with warm soapy water and a soft cloth; avoid harsh acidic cleaners that can etch certain accessory minerals; highly stable under normal environmental conditions
Rarity & Value
Very common; widely abundant across the Earth's continental crust; value is low for standard grades and moderate for decorative or unique ornamental varieties
Special Characteristics
Composed of an intergrowth of multiple primary rock-forming minerals, commonly featuring visible interlocking crystal boundaries characteristic of plutonic cooling
Lore & History
Historically used as a primary monumental and architectural stone by ancient Egyptians, Romans, and modern civilizations; in metaphysical lore, granite is often associated with strength, grounding, stability, and endurance, though these are traditional beliefs and not scientific claims