Red Granite
Phaneritic Igneous Rock (Granite) · Decorative Stone / Building Material
Crystal System
Isometric, Monoclinic, and Triclinic components in an interlocking mosaic
Mineral Group
Silicates (specifically Tectosilicates and Phyllosilicates)
Chemical Formula
SiO2 (major), KAlSi3O8, NaAlSi3O8, (Mg,Fe)3(Si,Al)4O10(OH)2
Formation Process
Igneous; slow cooling of silica-rich magma deep within the Earth's crust (plutonic formation)
About This Crystal
A coarse-grained, phaneritic rock featuring interlocking crystals of pink-to-red potassium feldspar, translucent grey quartz, and dark specks of biotite mica or hornblende. It is opaque with a predominantly dull to vitreous luster when polished.
Physical Characteristics
Mottled red, pink, grey, and black colors; white streak; typically massive with no cleavage as a rock, though individual minerals within it have specific cleavage; high density (~2.6-2.7 g/cm3).
Optical Properties
Largely opaque as a bulk rock; individual quartz crystals exhibit low birefringence; feldspars may show slight pearly luster or schiller.
Hardness & Durability
Origin Region
Global distribution, notably Egypt (Aswan), United States (Texas, Georgia), and Scandinavia
Hardness & Durability
Mohs hardness of 6 to 7; extremely tough and durable; high resistance to abrasion, weathering, and most household chemicals.
Care & Maintenance
Clean with mild soap and water; avoid highly acidic cleaners which can dull the surface over time; exceptionally resistant to sunlight fading and heat.
Rarity & Value
Very common; value is determined by the aesthetic pattern and color saturation; used extensively in architecture, monuments, and sculpture.
Special Characteristics
Features a 'salt and pepper' appearance; the presence of pink/red potassium feldspar provides the distinct coloration seen in the specimen.
Lore & History
Historically significant in Ancient Egypt for obelisks and sarcophagi due to its permanence; symbolically associated with groundedness, strength, and endurance in various cultural traditions.