Quartzite Arrowhead (Archaeological Lithic)
Recrystallized Quartz (SiO2)
metamorphic
Category
Mineraloid (Human Made Geological Specimen)
Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.
Sandstone (Ferruginous)
Arenite with Iron Oxide cement (primarily SiO2 with Fe2O3)
sedimentary
Milky quartz (likely vein quartz)
Quartz, silicon dioxide (SiO₂)
mineral
Carborundum (Silicon Carbide)
Silicon Carbide (SiC)
mineral (synthetic)
Banded Chert
Microcrystalline Quartz (SiO2)
sedimentary
Blue Goldstone
Synthetic Avanturine Glass (or Aventurine Glass)
Synthetic Glass
Granite
Granite (Silicic Intrusive Igneous Rock)
Igneous
Chert (Field-collected Arrowhead-shaped Fragment)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Jasper Marble
Silicon Dioxide (SiO2) with Impurities
sedimentary
Sandstone (with potential Arkose/Lithic characteristics)
Arenite (Sedimentary rock composed of sand-sized grains)
sedimentary
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Dyed Dragon Vein Agate
Silicon Dioxide (SiO2) with artificial pigment
mineral
Chert Pebble (Jasper variety)
Microcrystalline Quartz (SiO2)
sedimentary
Diamond (as set in a metal alloy ring)
Diamond (Pure Carbon, C)
mineral
White Opal
Hydrated Silica (SiO2·nH2O)
mineral
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Iron Ore / Ironstone Concretion
Mixture of iron oxide/hydroxide minerals, likely some combination of Hematite (Fe2O3), Goethite (α-FeOOH), and Limonite (a general term for hydrated iron oxides of variable composition) or potentially Bauxite (a mixture of aluminum hydroxides, often with iron oxides, (Al(OH)3) and FeO(OH)). The visual characteristics strongly suggest iron-rich material.
Mineral, specifically an iron ore
Chert (variations include Flint/Jasper)
Cryptocrystalline Quartz (SiO2)
sedimentary
Mahogany Obsidian
Volcanic glass containing Hematite or Magnetite (SiO2 + Fe2O3)
igneous
Quartzite
Metamorphic Quartzite (SiO2)
metamorphic
Limonite (Ironstone Concretion)
Limonite: FeO(OH)·nH2O
sedimentary
Blue Apatite
Apatite - Ca5(PO4)3(F,Cl,OH) (Calcium phosphate with Fluorine, Chlorine, or Hydroxyl)
mineral
Carnelian Agate
Silicon Dioxide (SiO2) - variety of Chalcedony
mineral
White Marble
Recrystallized Calcite Rock (CaCO3)
metamorphic
Felsic Drill Core (likely Gneiss or Granite)
Felsic Metamorphic Rock (Gneissic profile)
metamorphic
Tree Agate
Chalcedony (SiO2)
gemstone
Chert
Microcrystalline quartz (SiO2)
sedimentary
Obsidian Arrowhead
Volcanic Glass (70% or more SiO2)
Igneous
Granite
Phaneritic Felsic Igneous Rock (primarily Quartz, Feldspar, and Mica)
igneous
Shell Cameo
Cypraecassis rufa (Bullmouth Queen Helmet Shell)
mineraloid / biogenic specimen
Sandstone
Arenite
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
Quartzite
Metamorphosed Quartz Sandstone
metamorphic
Sandstone (Quartzose)
Sandstone (SiO2 dominated)
sedimentary
Diamond (in jewelry setting)
Adamantine Carbon (C)
mineral
Chert (Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Breccia
Breccia
sedimentary
Tumbled beige stone, possibly jasper or limestone
Indeterminate; likely microcrystalline quartz (jasper) or calcium-carbonate limestone
mineral
Pearl (Imitation or Cultured)
Calcium Carbonate (Aragonite/Calcite) - CaCO3
Mineraloid (Organic)
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (Iron-stained)
Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)
sedimentary