Amethyst (in jewelry)
Silicon Dioxide (SiO2) with iron impurities
Category
Browse granite specimens identified by the Rock Identifier community.
Amethyst (in jewelry)
Silicon Dioxide (SiO2) with iron impurities
Basalt
Mafic Igneous Rock (primarily Plagioclase Feldspar and Pyroxene)
Clear Quartz
Crystalline Silicon Dioxide (SiO2)
Green Quartz (Prasiolite)
Silicon Dioxide (SiO2) with trace impurities
Black Obsidian
Obsidian (Volcanic glass), 70–75% SiO2
Amethyst Geode
Silicon dioxide (SiO2) with iron impurities
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Gold Nugget
Native Gold (Au)
Petrified Wood
Silicified wood (primarily SiO2 - Silicon Dioxide)
Chert Pebble
Microcrystalline Quartz (SiO2)
Iron-Nickel Meteorite
Siderite (Meteoric Iron-Nickel alloy)
Clear Quartz
SiO2 (Silicon Dioxide)
Olivine (in Peridotite/Dunite form)
Magnesium Iron Silicate (Mg,Fe)2SiO4
Amethyst
Silicon Dioxide (SiO2) with iron impurities
Flint Nodule
Microcrystalline Quartz (SiO2)
Diamond (in jewelry setting)
Carbon (C)
Green Aventurine (Carved)
Silicon Dioxide (Quartz variant) with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O(OH)2)
Gold Nugget
Native Gold (Au)
Erythrite (or Lab-Grown Cobaltite/Cinnabar Analog)
Erythrite (Co3(AsO4)2·8H2O)
Copper Bullion Round
Native Copper (refined), Cu
Pyrite (Fool's Gold)
Iron Disulfide (FeS2)
Milky Quartz
Silicon Dioxide (SiO2)
Limonite/Hematite Ironstone
Goethite-rich Ironstone (FeO(OH) · nH2O)
Chert (Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
Basalt
Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
Diamond (set in Gold)
Carbon (C)
Diamond
Diamond (Pure Carbon, C)
Chert (containing a small fossil)
Microcrystalline Quartz (SiO2)
Banded Calcite (often sold as Mexican Onyx or Aragonite)
Calcite/Aragonite (Calcium Carbonate, CaCO3)
Citrine
Silicon Dioxide (SiO2)
Quartz Druzy Geode Fragment
Silicon Dioxide (SiO2)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Clear Quartz Crystal
Silicon Dioxide (SiO2)
Nacre (Mother of Pearl)
Nacre (Biogenic Aragonite/Calcite composite, CaCO3)
White Marble
Recrystallized Calcite (CaCO3) / Marble
Azurite
Azurite (Cu3(CO3)2(OH)2)
Chert (White Chert or Flint)
Microcrystalline or cryptocrystalline quartz (SiO2)
Basalt (River Pebble)
Extrusive Magic Igneous Rock (Mainly Plagioclase and Pyroxene)
Sandstone (Quartzose Pebble)
Clastic sedimentary rock (primarily SiO2)
Hematite
Iron(III) oxide (Fe2O3)
Coal (Bituminous or Anthracite)
Carbonaceous sedimentary rock (primarily Carbon, C)
Emerald (Tumbled Beryl)
Beryllium Aluminum Silicate (Be3Al2Si6O18) with Chromium/Vanadium impurities