Gemstone profile and identification guide
Clear Quartz
Clear quartz (rock crystal) is colorless transparent quartz with trigonal crystal symmetry and vitreous lustre.
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Overview
Clear quartz (rock crystal) is colorless transparent quartz with trigonal crystal symmetry and vitreous lustre.
Did you know? Large rock crystal spheres and carvings have been produced for centuries from Brazilian material.
Use this profile as a collector reference and educational guide for quick on-page comparison, then validate with the interactive identification system.
Identification
Name: Clear Quartz
Scientific classification: Silicate (Quartz)
Hardness: 7 Mohs
Transparency: transparent
Lustre: vitreous
Crystal system: Trigonal
Primary colour: Colorless
Secondary colour: Not specified
Colour family: Whites & Neutrals
Diagnostic properties include RI 1.544-1.553, birefringence 0.009, no cleavage, and conchoidal fracture.
Verification Status
Status: verified-core-fields
Reference priority: GIA, Gem-A, Mindat, International Gem Society
Core identity, locality, and physical-property fields reviewed against standard gemological references.
Values are given as practical gemological ranges where appropriate.
Physical Properties
Hardness category: hard
Hardness value: 7 Mohs
Chemical composition: Silicon dioxide (SiO2)
Crystal system: Trigonal
Common locations: Brazil, Madagascar, United States (Arkansas), China, Switzerland (Alps)
Learn more: Gem-A gemstone education resources.
Colour Variations
Colorless transparent quartz, also known as rock crystal.
Optical effects: None specified in the current dataset.
Detailed Gemology
Mineral species: Quartz
Mineral group: Quartz group
Chemical formula: Silicon dioxide (SiO2)
Mohs hardness: 7
Crystal system: Trigonal
Lustre: vitreous
Transparency: transparent
Streak: White
Cleavage: None
Fracture: Conchoidal
Specific gravity: 2.65
Refractive index: 1.544-1.553
Optical phenomena: None typically diagnostic
Colour range: Colorless
Common inclusions: Veils, fluid inclusions, twinning, negative crystals
Geological environment: Hydrothermal veins, pegmatites, and metamorphic fissures
Principal mining regions: Brazil, Madagascar, United States (Arkansas), China, Switzerland (Alps)
Important commercial sources: Commercial clear quartz is abundant, with major supply from Brazil and Madagascar
Historical significance: Rock crystal has long been used for carvings, lenses, and ornamental objects.
Common treatments: Generally untreated; coated or irradiated products are sold under separate trade names.
Synthetic or imitation forms: Hydrothermal synthetic quartz and glass imitations are common.
Common look-alikes: Glass, synthetic spinel, colorless topaz
Jewellery uses: Used for faceted gems, carvings, beads, and mineral specimens.
Care recommendations: Durable for normal wear. Clean with mild soap; avoid impacts that can chip facet edges.
Cross-check profile data with GIA Gem Encyclopedia and Mindat entry for Clear Quartz.
Formation
Forms in hydrothermal veins, pegmatites, and alpine fissures from silica-rich fluids.
Origin
Commercial clear quartz is abundant, with major supply from Brazil and Madagascar
Uses
Best for: Used for faceted gems, carvings, beads, and mineral specimens.
Ideal uses: Faceted jewellery, carvings, and collector crystal specimens.
Care
Durable for normal wear. Clean with mild soap; avoid impacts that can chip facet edges.
Need another candidate? Use advanced gemstone search or return to the identification guide.
Related gemstones by colour
Related gemstones by hardness
Gemstones from the same mineral family
Commonly confused gemstones
Clear Quartz FAQ
How can I identify Clear Quartz?
Compare hardness (7 Mohs), crystal system (Trigonal), colour profile, and lustre (vitreous) with your sample. Then cross-check related gemstones listed above.
What colour range does Clear Quartz appear in?
Colorless transparent quartz, also known as rock crystal.
Where is Clear Quartz commonly used?
Faceted jewellery, carvings, and collector crystal specimens.. For maintenance, follow the care guidance in this profile.
Scientific References
GIA: general gemstone identity (reviewed) - Batch 01 factual verification pass.
Gem-A: gemological terminology and testing references (reviewed) - Batch 01 factual verification pass.
Mindat: mineral species and principal localities (reviewed) - Batch 01 factual verification pass.
International Gem Society: gem trade context and treatment overview (reviewed) - Batch 01 factual verification pass.