Snowflake Obsidian
Obsidian with Cristobalite inclusions (70–75% SiO2)
igneous
Category
Not A Geological Specimen
Browse not a geological specimen specimens identified by the Rock Identifier community.
Banded Chert in Matrix
Microcrystalline Quartz (SiO2)
sedimentary
Fossiliferous Limestone
Biogenic Limestone (Calcium Carbonate, CaCO3)
sedimentary
Limonite (Bog Iron)
Limonite (Hydrated iron(III) oxide-hydroxide) - FeO(OH)·nH2O
mineral
Black Tourmaline (Schorl)
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
mineral
Sandstone concretion (Ironstone-stained)
Arenite with Limonite/Hematite staining (Silica-based with Iron Oxides)
sedimentary
Quartz Druze on Matrix (Geode Fragment)
Quartz (Silicon Dioxide, SiO2)
mineral
Red Sandstone
Arenite (primarily Quartz with Hematite cement)
sedimentary
Kunzite
Spodumene (LiAlSi2O6), variety Kunzite
Mineral
Ferruginous Quartz (Iron-stained Quartz)
Quartz with Iron Oxide inclusions (SiO2 with Fe2O3)
mineral
Green Fluorite
Calcium Fluoride (CaF2)
mineral
Opalite
Synthetic Opalised Glass
Mineral (Synthetic / Man-made)
Moqui Marble (Shaman Stone)
Iron Oxide Concretion (Limonite/Hematite over Sandstone)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Tektite (Indochinite)
Tektite (Lechatelierite-rich silica glass)
Mineral-like (Natural Glass)
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Diamond (set in Gold)
Carbon (C)
mineral
Diamond (appearing in jewelry)
Diamond (pure Carbon, C)
mineral
Quartz
SiO₂ (Silicon Dioxide)
Mineral
Dalmatian Stone
Dalmatian Jasper / Feldspathic Igneous Rock
igneous
Agate with Quartz Druzy
Silicon Dioxide (SiO2) - Microcrystalline and Macrocrystalline varieties
mineral
Quartz (Pale Rose or Milky Variety)
Silicon Dioxide (SiO2)
mineral
Amber
Succinite (specifically for Baltic amber; general formula C10H16O)
Mineraloid (Organic)
Jade (Nephrite or Jadeite)
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2) or Jadeite (Na(Al,Fe3+)Si2O6)
Metamorphic Rock / Mineral
Limonite and Goethite encrusted Quartz (Iron-stained Gossan)
FeO(OH)·nH2O (Limonite) / FeO(OH) (Goethite) on SiO2 (Quartz)
mineral
Quartz (Iron-stained)
Silicon Dioxide (SiO2)
mineral
Quartzite
Quartzite (primarily SiO2)
metamorphic
Sandstone (with man-made markings)
Arenite (composed primarily of Quartz, SiO2)
sedimentary
Quartz (Smoky/Milky variety with matrix)
Silicon Dioxide (SiO2)
mineral
Bauxite
Hydrated Aluminum Oxides (primarily Gibbsite Al(OH)3, Boehmite γ-AlO(OH), and Diaspore α-AlO(OH))
sedimentary
Fluorite (Polished Point/Tower)
Calcium Fluoride (CaF2)
mineral
Fossiliferous Limestone
Biogenic Calcium Carbonate (CaCO3)
sedimentary
Feldspar-rich Granite (Pink Granite)
Phaneritic Felsic Igneous Rock
igneous
Ferruginous Sandstone
Clastic Sedimentary Rock (Iron-rich)
sedimentary
Granite Pebble
Granite (Phaneritic Quartz-Feldspar intrusive rock)
igneous
Granite Pebble
Felsic Plutonic Rock (primarily Quartz, Feldspar, and Mica)
igneous
Fossilized Brachiopod/Bivalve in Limestone
Brachiopoda or Bivalvia fossil in Calcite/Limestone (CaCO3)
sedimentary
Tourmalinated Quartz
Silicon Dioxide (SiO2) with Schorl inclusions (NaFe2+3Al6(BO3)3Si6O18(OH)4)
mineral
Quartz Pebble (Chert/Chalcedony)
Silicon Dioxide (SiO2)
mineral
Quartzite with Iron inclusions
Metamorphosed Sandstone (SiO2 with Fe2O3)
metamorphic
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Amber
Succinite (fossilized resin); C10H16O
mineraloid