Coal (Anthracite / Bituminous)
Organic Sedimentary Rock (Carbon-based)
sedimentary
Category
Man Made Material (Jewelry, Metal Alloy)
Browse man made material (jewelry, metal alloy) specimens identified by the Rock Identifier community.
Learn about Man Made Material (Jewelry, Metal Alloy) in the encyclopedia
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Chert (Nodule)
Chert (SiO2)
sedimentary
Chert (and Flint)
Silicon Dioxide (SiO2)
sedimentary
Rough Corundum (Sapphire/Ruby mixture)
Corundum (Aluminum Oxide, Al2O3)
mineral
Chalcedony (or a variety of Chalcedony, likely Agate or Jasper)
Chalcedony (SiO₂)
Mineral (or mineraloid if microcrystalline)
Sandstone
Arenite
sedimentary
Aquamarine
Beryl (Be3Al2Si6O18 with iron impurities)
mineral
Sandstone
Clastic sedimentary rock (Quartz arenite/Arkose)
sedimentary
White Marble
Recrystallized Calcite (CaCO3)
metamorphic
Hematite (Iron Ore Boulder)
Hematite (Fe2O3)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Fossil Sea Urchin (Echinoid)
Echinoidea fossil (often replaced by silica or calcite)
fossil
Diamond (or Cubic Zirconia simulant)
Carbon (C) - Diamond / Zirconium dioxide (ZrO2) - CZ
mineral
Unakite
Altered Granite (Epidotized Granite)
metamorphic
Corundum (Pink Sapphire / Ruby)
Al2O3 (Aluminum Oxide)
mineral
Beaded Jewelry (Assorted Gemstones)
Various minerals, including but not limited to Quartz (SiO2), Garnet (X3Y2(SiO4)3), Jade (Na(Al,Fe)Si2O6), Amethyst (SiO2),等の多様な組み合わせ
Mineral, Jewelry
Granite Cobble/Pebble
Granite
Igneous
Polished blue-green glassy slag or coated mineral fragment
Most likely man-made colored glass/slag; exact composition cannot be determined visually
mineral
Green Aventurine
Silicon Dioxide with Fuchsite (SiO2)
mineral
Granite
Granite (a common rock type, not a single mineral with a formula. Composed primarily of quartz, feldspar, and mica/amphibole).
igneous
Quartzite
Quartzite (primarily SiO2)
metamorphic
Gold Nugget
Native Gold (Au)
mineral
Sandstone
Arenite
sedimentary
Sea Glass (Frosted Glass)
Amorphous Silica (SiO2) with various additives
Man-made material (Anthropogenic 'mineraloid')
Pink Opal
Hydrated Silica (SiO2·nH2O) with Palygorskite/Sepiolite inclusions
gemstone
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
mineral
Greenstone
Greenschist (composed of actinolite, chlorite, and epidote)
metamorphic
Diamond
Carbon (C)
mineral
Carbonaceous Chondrite (CV3 type)
Carbonaceous Chondrite (CV3 group)
meteorite
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Nodule/Pebble)
Chert (Silicon Dioxide, SiO2)
sedimentary
Chert (Jasper/Flint variant)
Silicon Dioxide (SiO2)
sedimentary
Diamond (Colorless/White)
Carbon (C)
mineral
Green Onyx
Chalcedony (Silicon Dioxide, SiO2)
gemstone
Rose Quartz
Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese
mineral
Diamond
Carbon (C)
gemstone
Sandstone (likely Fossiliferous)
Arenite / Fossiliferous Sandstone (SiO2 composition)
sedimentary
Dyed blue howlite (turquoise imitation), possibly dyed magnesite
Howlite: Ca₂B₅SiO₉(OH)₅; the vivid blue color is artificial dye. Exact identification is uncertain from the photograph alone.
gemstone
Slate
Metamorphic pelitic rock
metamorphic
Coquina / Fossiliferous Limestone
Coquina (composed primarily of Calcium Carbonate / CaCO3)
sedimentary
Sandstone (with iron staining)
Quartz Arenite / Ferruginous Sandstone
sedimentary
Fossil Shark Tooth
Lamniform (Mackerel Shark) fossil tooth, likely Otodus or Cretalamna
fossil