Almandine Garnet
Almandine (Fe3Al2(SiO4)3)
mineral
Category
Mixed (Predominantly Sedimentary And Igneous)
Browse mixed (predominantly sedimentary and igneous) specimens identified by the Rock Identifier community.
Learn about Mixed (Predominantly Sedimentary And Igneous) in the encyclopedia
View all →
Yellow Quartz (Citrine or Yellow Chalcedony)
Silicon Dioxide (SiO2)
mineral
Citrine
Silicon Dioxide (SiO2)
mineral
Mixed river pebbles and quartz-rich specimens
Polymictic fluvial gravel; likely quartz, quartzite, chert, and weathered feldspathic rocks
sedimentary
Quartz-rich rock fragments, likely granite or gneiss
Granite/gneiss assemblage; chiefly quartz (SiO₂), feldspar, and mica
igneous
Amethyst
Silicon dioxide (SiO2) with iron impurities
mineral
Yellow Quartz (Citrine Quartzite)
Silicon Dioxide (SiO2)
mineral
Rose Quartz
Silicon Dioxide with trace inclusions (SiO2)
mineral
Iron-rich concretion (probable limonite/goethite concretion)
Hydrated iron oxides, chiefly limonite (FeO(OH)·nH₂O) and goethite (FeO(OH))
sedimentary
Unakite
Epidotized Granite
metamorphic
Sandstone (likely Quartzose Sandstone)
Arenite (SiO2 predominantly)
sedimentary
Granite Cobble
Phaneritic Plutonic Felsic Rock
igneous
Concrete with Exposed Aggregate
Anthropogenic conglomerate (Concrete)
man-made rock (sedimentary analogue)
Limonite Ironstone
Goethite-Limonite concretion / Iron oxide
sedimentary
Limonite Nugget
Limonite (Hydrated iron oxide-hydroxide, FeO(OH)·nH2O)
mineral
Granite
Intrusive Igneous Rock
igneous
Granite
Intrusive Igneous Rock
igneous
K-Feldspar (Potassium Feldspar)
Potassium Feldspar (Microcline or Orthoclase), KAlSi3O8
mineral
Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Quartz Crystal (specifically Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Vein-filled Sedimentary Rock
Silicified sedimentary rock with quartz/calcite vein
sedimentary
Pyrite-bearing sulfide specimen
Pyrite (FeS₂), possibly mixed with chalcopyrite or other iron sulfides
mineral
Mixed River Pebbles (Jasper, Hematite, and Quartzites)
Silicon dioxide (Jasper/Quartz) and Iron oxide (Hematite)
sedimentary
Sandstone
Arenite (SiO2 predominantly)
sedimentary
Anthracite Coal
Coal (predominantly carbon)
sedimentary
Sandstone River Cobble
Arenite (predominantly SiO2)
sedimentary
Sandstone (Quartzose)
Arenite (predominantly SiO2)
sedimentary
Topaz
Al2SiO4(F,OH)2
mineral
Granite
Intrusive Igneous Rock
igneous
Black Tourmaline
Schorl (Na(Fe²⁺)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)
mineral
Tektite (Indochinite)
Tektite (Natural silica glass)
igneous
Epidosite (Epidote-rich rock)
Epidosite (consisting primarily of Epidote: {Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH))
metamorphic
Obsidian Jewelry Piece
Volcanic Glass (SiO2 + impurities)
igneous
Greywacke (River Pebble)
Greywacke sandstone with quartz veining
sedimentary
Mahogany Obsidian
Volcanic glass (SiO2 with Hematite or Magnetite inclusions)
igneous
Sandstone
Arenite (predominantly SiO2)
sedimentary
Mixed rounded fieldstones, likely granite and gneiss
Granite (quartz–feldspar–mica) and gneiss; exact identification is uncertain from the photograph
igneous and metamorphic
Asphalt Concrete
Bituminous Concrete / Asphaltic Composite
not a natural rock (man-made composite)
Mixed River Pebbles and Rock Collection
Polymictic lithic conglomerate, sandstone, and quartz pebbles
sedimentary
Green Aventurine
Aventurine Quartz (SiO2 with Fuchsite inclusions)
mineral
Azurite and Malachite
Cu3(CO3)2(OH)2 (Azurite) / Cu2CO3(OH)2 (Malachite)
mineral
Chrysocolla in Matrix
Chrysocolla (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral