Amethyst
Silicon Dioxide (SiO2)
mineral
Category
Crystal
Browse crystal specimens identified by the Rock Identifier community.
Amethyst on Agate
Crystalline Quartz (SiO2) with trace Iron (Fe3+)
mineral
Amethyst (rough crystal cluster)
Quartz, SiO₂; purple coloration commonly caused by trace iron and natural irradiation
mineral
Unidentified translucent crystal/mineral fragment
Likely quartz (SiO₂), but visual identification is uncertain
mineral
Cut diamond tennis-chain jewelry
Diamond, crystalline carbon (C), cubic crystal system
gemstone
Agate Geode
Silicon Dioxide (SiO2) - Variety Agate with Quartz crystal center
mineral
Rainbow carborundum (silicon carbide)
Silicon carbide, SiC; commonly synthetic moissanite/carborundum specimen
mineral
Kyanite (Blue or Blue-Grey)
Kyanite (Al2SiO5)
metamorphic mineral
Raw blue-green apatite crystal
Apatite group, likely fluorapatite — Ca₅(PO₄)₃F
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Emerald in Matrix
Beryllium Aluminum Silicate (Be3Al2(SiO3)6) with Chromium/Vanadium
gemstone
Raw Emerald (Emerald Beryl)
Beryl (Be3Al2Si6O18) with chromium/vanadium impurities
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Aquamarine
Beryl (Be₃Al₂Si₆O₁₈)
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Aquamarine
Beryl (Be3Al2Si6O18 with Fe2+ impurities)
mineral
Rose Quartz
Silicon Dioxide (SiO2)
gemstone
Polished agate geode
Chalcedony (microcrystalline quartz, SiO₂) with quartz druse crystals
mineral
Geode with Quartz Crystals
SiO2 (Silicon Dioxide) in a geode formation
Sedimentary/Igneous (depending on host rock)
Quartz Crystal Matrix
Silicon Dioxide (SiO2)
mineral
Almandine garnet crystal
Almandine, an iron-aluminum garnet; ideal formula Fe₃Al₂(SiO₄)₃
mineral
Rose quartz
Quartz, SiO₂ (pink variety; trigonal crystal system)
mineral
Diamond cluster ring (likely jewelry setting)
Diamond, crystalline carbon (C), cubic crystal system
gemstone
Quartz crystal cluster (likely rose or milky quartz)
Quartz, silicon dioxide (SiO₂); trigonal crystal system
mineral
Amethyst
Amethyst (SiO2 with Iron impurities)
mineral
Desert rose (gypsum)
Gypsum, CaSO₄·2H₂O; commonly a rosette of bladed gypsum crystals, sometimes with sand inclusions
mineral
Quartz crystal cluster
Quartz (SiO₂), likely milky quartz
mineral
Amethyst druzy geode fragment
Amethyst, purple variety of quartz (SiO₂), with druzy quartz crystals
mineral
Aquamarine
Beryl (Be3Al2Si6O18)
mineral
Green Quartz
Silicon Dioxide (SiO2)
mineral
Polished agate/geode slab
Banded chalcedony (microcrystalline quartz, SiO₂), likely with quartz crystals
mineral
Amethyst Geode
Quartz (SiO2)
mineral
Crackled Quartz (Blue Dyed)
Silicon Dioxide (SiO2) with anthropogenic dye
mineral
Native bismuth
Bismuth (Bi), commonly forming hopper crystals or aggregates
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
gemstone
Quartz crystals on Basalt
SiO2 (Quartz) on Mafic Igneous Rock (Basalt)
igneous
Milky quartz (likely quartz crystal fragment)
Quartz, silicon dioxide (SiO₂)
mineral
Herkimer Diamond (Quartz)
Silicon Dioxide (SiO2)
mineral