Gneiss
Gneiss (High-grade Metamorphic Rock)
metamorphic
Category
Mineral (Native Element Alloy)
Browse mineral (native element alloy) specimens identified by the Rock Identifier community.
Dinosaur Bone (Fossilized)
Permineralized Bone (CaCO3 or SiO2 after Hydroxylapatite)
sedimentary
Banded Agate (Tumbled)
Agate (Variety of Chalcedony/Quartz), SiO2
mineral
Pyrite in Matrix (likely Quartz or Coal)
Iron Sulfide (FeS2)
mineral
Greenschist (Greenstone River Pebble)
Greenschist (Chlorite Schist)
metamorphic
Blue Quartzite
Quartzite (specifically a variety enriched with blue-coloring minerals)
Metamorphic Rock
Pyrite in Matrix (Fool's Gold)
Iron Disulfide (FeS2)
mineral
Schorl (Black Tourmaline)
Sodium Iron Aluminum Borosilicate Hydroxide - NaFe2+3Al6Si6O18(BO3)3(OH)3OH
mineral
Obsidian
Obsidian (Amorphous volcanic glass, SiO2 rich)
igneous
Quartz with Hematite Staining
Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) inclusions
mineral
Lepidolite
K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2
mineral
Diamond
Diamond (C)
mineral
Labradorite
Labradorite (a calcium-enriched feldspar mineral), (Ca, Na)(Al, Si)4O8
mineral
Red Garnet
Almandine and Pyrope (Silicate minerals: Fe3Al2(SiO4)3 and Mg3Al2(SiO4)3)
mineral
Nephrite (a form of Jade)
Nephrite (a variety of the mineral actinolite, Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral
Limonite-pseudomorph after Pyrite (Prophecy Stone)
Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)
mineral
Granite
Phaneritic Felsic Igneous Rock (Main minerals: SiO2, KAlSi3O8, NaAlSi3O8)
igneous
Green Aventurine
Aventurine (variety of Quartz - SiO2)
Mineral_Rock
Schist
Crystalline Metamorphic Rock (Schistose)
metamorphic
Basalt (with possible mineral veining)
Basalt (Aphanitic Mafic Igneous Rock)
Igneous
Quartzite with Iron Mineral Banding
Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3) staining
metamorphic
Dyed Agate
Silicon Dioxide (SiO2) - variety Chalcedony
mineral
Petrified Wood
Silicified wood (primarily Silicon Dioxide, SiO2)
sedimentary
Ferruginous Sandstone
Sandstone (rich in iron oxides/hydroxides)
sedimentary
Green Aventurine
Quartz with Fuchsine inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)
mineral
Pyrite in Matrix (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Fluorite
Calcium Fluoride (CaF2)
mineral
Slate
Slate (a fine-grained, foliated metamorphic rock). Mineral composition: Primarily composed of mica minerals (muscovite, chlorite, sericite) and quartz, with minor amounts of hematite, pyrite, and other accessory minerals.
sedimentary
Howlite and Purpurite druzy
Calcium Borosilicate Hydroxide (Howlite) and Manganese Phosphate (Purpurite)
mineral
Tumbled Moonstone
Feldspar (Orthoclase/Albite), KAlSi3O8
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Satin Spar (often sold as Selenite)
Gypsum (CaSO4·2H2O)
mineral
Sandstone
Arenite (SiO2 primarily)
sedimentary
Chrysocolla
Chrysocolla, (Cu, Al)2H2Si2O5(OH)4·nH2O
mineral
Granite Cobble
Granite
igneous
Geode (Unopened)
Silica Concretion / Geode (Formula: SiO2 for quartz internal contents)
sedimentary
Granite
Granite (Felsic intrusive igneous rock)
igneous
Charoite
Charoite (Hydrated potassium, sodium, calcium, barium, strontium silicate hydroxide fluoride)
metamorphic
River Stone (Granitic Gneiss)
Foliated Granitic Gneiss
metamorphic
Gneiss
Gneiss
metamorphic
Copper-bearing Quartz (likely Malachite on Quartz matrix)
Cu2CO3(OH)2 (Malachite) on SiO2 (Quartz)
mineral
Greenstone
Metabasalt / Greenschist facies rock
metamorphic