Ironstone (Limonite/Goethite Concretion)
Ferruginous Sedimentary Rock (composed of Goethite FeO(OH) and Limonite)
sedimentary
Category
Man Made Byproduct (Often Mistaken For Obsidian Or Emerald)
Browse man made byproduct (often mistaken for obsidian or emerald) specimens identified by the Rock Identifier community.
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Obsidian
Volcanic Glass (SiO2)
igneous
Obsidian
Obsidian
Igneous
Sandstone
Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)
Sedimentary Rock
Jasper (Multi-colored) / Sea Glass Slag
Silicon Dioxide (SiO2) with impurities of Iron Oxide
Sedimentary (if natural Jasper) or Artificial (if Slag)
Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Sedimentary Rock (Quartz Sandstone)
sedimentary
Costume Jewelry Gemstones (Emerald-imitation and semi-precious beads)
BeCuAl6Si6O18 (Beryl structure), frequently simulated by glass or synthetic spinel
mineral
Emerald
Beryl (Be3Al2(SiO3)6)
gemstone
Dendritic Agate
Silicon Dioxide (SiO2) with Manganese/Iron oxide inclusions
mineral
Obsidian
Volcanic Glass (predominantly SiO2)
igneous
Yellow Jade
Jadeite or Nephrite (NaAlSi2O6 or Ca2(Mg,Fe)5Si8O22(OH)2)
metamorphic
Obsidian
Volcanic Glass (Amorphous Silicon Dioxide)
igneous
Tiffany Stone
Bertrandite-Bearing Fluorite Hyalite Opal
metamorphic
Blue Dumortierite in Quartz
Al7(BO3)(SiO4)3O3 (Dumortierite)
mineral
Obsidian
Volcanic Glass (SiO2 rich)
igneous
Diamond
Carbon (C)
mineral
Quartzite
Metamorphic Quartz Arenite
metamorphic
Ironstone Concretion (Desert Varnish / Hematite-Goethite Nodule)
Iron oxide / hydroxide deposit (predominantly Fe2O3 and FeO(OH))
sedimentary
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide)
igneous
Quartzite (Gold-toned)
Crystalline Quartz Metamorphite (SiO2)
metamorphic
Dendritic Agate (Tree Agate)
Chalcedony (Silicon Dioxide, SiO2) with Manganese or Iron Oxide inclusions
mineral
Pebble (likely Quartz or Chert)
SiO₂ (Silicon Dioxide) - referring to the likely main mineral composition, Quartz. If it's chert, the scientific name remains SiO₂ with a microcrystalline structure.
Sedimentary Rock
Dendritic Agate (River Pebble)
Silicon Dioxide (SiO2) with Manganese or Iron oxide inclusions
mineral
Iron-stained Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
mineral
Obsidian
Volcanic Glass (70% or more SiO2)
igneous
Orange Calcite
Calcite (Calcium Carbonate - CaCO3)
mineral
Quartzite with Hematite staining
Quartzite (SiO2)
metamorphic
Emerald
Beryl (Be3Al2(SiO3)6)
gemstone
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Dendritic Jasper (River Stone)
Silicon Dioxide (SiO2) with Manganese/Iron Oxide inclusions
sedimentary
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
mineral
Obsidian
Obsidian (Volcanic Glass, SiO2 + impurity)
Igneous
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
mineral
Emerald
Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities
mineral
Peridot
Olivine (Mg, Fe)2SiO4
mineral
Dendritic Opal
Opalized Chalcedony with Manganese Inclusions (SiO2 · nH2O)
mineral
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
igneous
Ironstone Concretion / Goethite-Hematite Nodule
Goethite/Hematite (α-FeO(OH) / Fe2O3)
sedimentary
Quartzite
Meta-quartzite (SiO2)
metamorphic
Milky Quartz with Dendritic Inclusions
Silicon Dioxide (SiO2)
mineral
Emerald
Beryl (Be3Al2Si6O18 with Chromium/Vanadium impurities)
mineral