Amethyst (likely rough or cleaved fragment)
Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation
mineral
Category
Mineral (Man Made Glass, Not Natural)
Browse mineral (man made glass, not natural) specimens identified by the Rock Identifier community.
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Granodiorite
Phaneritic Plutonic Intermediate-Felsic Rock
igneous
Chert Pebble/Nodule
Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)
Sedimentary
Quartz Pebble (Iron-stained)
Silicon Dioxide (SiO2)
sedimentary
Smoky Quartz
Silicon Dioxide (SiO₂)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Diamond (or Cubic Zirconia simulant)
Carbon (C) or Zirconium Dioxide (ZrO2)
mineral
Sandstone (Ferruginous)
Sandstone (primarily SiO2 with iron oxide cement Fe2O3)
sedimentary
Diamond (or Lab-Grown Cubic Zirconia)
Carbon (C)
mineral
Citrine Quartz
Crystalline Quartz (SiO2 with iron impurities)
mineral
Tektite (Indochinite)
Tektite (Amorphous Silica Glass)
igneous
Red Quartzite
Quartzite (Metamorphic quartz sandstone)
metamorphic
Yellow Quartz (Citrine-colored Quartz)
Silicon Dioxide (SiO2)
mineral
Sand and Gravel (Quartz-rich)
Unconsolidated fluvial/beach sediment (primarily Silica/SiO2)
sedimentary
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 staining)
sedimentary
Dyed Chalcedony (Agate)
Silicon Dioxide (SiO2) with artificial pigment
mineral
Quartz (Engineered Stone Countertop)
Silicon Dioxide (SiO2) within a resin matrix
igneous
Smoky Quartz
SiO2 (Silicon Dioxide)
Mineral
Black Onyx
Cryptocrystalline Quartz (SiO2)
mineral
Smoky Quartz
Smoky Quartz (SiO2)
mineral
Smoky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Milky Quartz with Iron Inclusions
Quartz (Silicon Dioxide, SiO2)
mineral
US Penny
Cuprum (Copper: Cu) and Zincum (Zinc: Zn) Alloy
Man-made object (metal alloy)
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Clastic Sedimentary Rock
sedimentary
Jasper and Chalcedony Nodule
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Amethyst (Purple Quartz)
Silicon Dioxide (SiO2) with iron impurities
mineral
Clear Quartz
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2)
mineral
Smoky Quartz
Silicon Dioxide (SiO2) with aluminum impurities
mineral
Citrine Quartz
Silicon Dioxide (SiO2) with iron impurities
mineral
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
mineral
Citrine
Silicon dioxide (SiO2)
mineral
Smoky Quartz
Silicon dioxide (SiO2)
mineral
Sandstone (Quartzose Sandstone)
Sandstone (SiO2 with various trace minerals)
sedimentary
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
igneous (artificial/anthropogenic)
Smooth gray river pebble
Likely fine-grained sandstone or siltstone; exact identification requires a fresh surface and tests
sedimentary
Green Aventurine
Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)
mineral
Amethyst
Quartz (Silicon Dioxide, SiO2) with iron impurities
mineral
Amethyst
Quartz (Silicon Dioxide, SiO2)
gemstone
Yellow jasper or polished yellow chalcedony
Microcrystalline quartz, SiO₂, likely iron-stained jasper/chalcedony
mineral
Quartz Crystal (specifically a Double-Terminated variety)
Silicon Dioxide (SiO2) - Low Quartz
mineral