Granite
Granite (a felsic intrusive igneous rock composed primarily of quartz, feldspar, and mica)
igneous
Category
Sedimentary Rock (Possibly Composed Of Various Minerals)
Browse sedimentary rock (possibly composed of various minerals) specimens identified by the Rock Identifier community.
Learn about Sedimentary Rock (Possibly Composed Of Various Minerals) in the encyclopedia
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Quartz
Silicon Dioxide (SiO2)
mineral
Sandstone
Arenite (primarily SiO2)
sedimentary
Siltstone
Siltstone (composed of mixed silicate minerals and clay)
sedimentary
Siltstone with Weathering Rind
Siltstone (composed of microscopic quartz and clay minerals)
sedimentary
Jasper
Silicon Dioxide (Microcrystalline Quartz, SiO2)
sedimentary
Limonite (Iron Stone Concretion)
Limonite (Hydrous Iron Oxide) - FeO(OH)·nH2O
mineral
Moss Agate
Chalcedony (Silicon Dioxide, SiO2) with inclusions
mineral
Rounded basalt pebble
Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine
igneous
Basalt
Mafic Igneous Rock (composed primarily of Pyroxene and Plagioclase Feldspar)
igneous
Coal (Bituminous)
Sedimentary carbonaceous rock
sedimentary
Diorite
Plutonic Igneous Rock (Intermediate Composition)
Igneous
Weathered granite or granitic gneiss pebble
Granite, primarily quartz, feldspar, and mica; possibly weakly foliated gneiss
igneous
Sandstone (with Iron concretions/staining)
Arenite (composed primarily of Quartz and Feldspar with Iron Oxide cement)
sedimentary
Sandstone (Ferruginous)
Arenite (composed primarily of SiO2 with Fe2O3 cement)
sedimentary
Epidote
Epidote (formula: Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))
mineral
Clear Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
mineral
Mica Schist (with Muscovite mica)
Mica Schist (KAl2(AlSi3O10)(OH)2)
metamorphic
Yellow Jasper
Silicon dioxide (SiO2)
sedimentary
Jasper
Silicon dioxide (Microcrystalline quartz, SiO2)
mineral
Quartz Geode
Silicon Dioxide (SiO2)
sedimentary
Vesicular Basalt with Quartz/Chalcedony
Vesicular Basalt (primarily Plagioclase, Pyroxene, and Olivine with SiO2 infill)
igneous
Iron-stained quartz vein rock
Milky quartz (SiO₂) with limonite/goethite iron oxides, possibly in altered host rock
metamorphic
Basalt-Amugydule (Amygdaloidal Basalt)
Aphanitic Mafic Igneous Rock with Vesicle Infillings
igneous
Quartz Geode
Silicon Dioxide (SiO2) within a secondary sedimentary structure
sedimentary
Aventurine (likely Green Aventurine)
Silicon Dioxide (SiO2) with mineral inclusions
Mineral/Mineraloid within a rock matrix
Likely milky quartz with iron-oxide inclusions
Quartz, silicon dioxide (SiO₂)
mineral
Slate
Foliated Metamorphic Rock (Mainly composed of Quartz, Illite, Chlorite)
metamorphic
Sandstone (Greywacke/Siltstone variant)
Clastic Sedimentary Rock (composed primarily of Quartz SiO2 and Feldspar)
sedimentary
Green Opal
Hydrated amorphous silica (SiO2·nH2O) with inclusions
mineraloid
Quartz-rich rock, likely milky quartz or quartzite
Quartz (SiO₂); possibly quartzite, a recrystallized quartz sandstone
metamorphic
Siltstone / Shale River Rock
Siltstone (primarily SiO2 with Al2O3)
sedimentary
Granite Gneiss
Felsic Gneiss (composed of Quartz, Feldspar, and Biotite)
metamorphic
Dalmatian Stone
Peralkaline Feldsphathic Igneous Rock
igneous
Banded sandstone pebble
Quartz-rich sandstone, likely with a contrasting siltstone or fine-grained sandstone band
sedimentary
Conglomerate
Conglomerate
Sedimentary Rock
Quartz
Silicon Dioxide (SiO2)
mineral
Petrified Wood
Silicified Wood (SiO2)
sedimentary
Likely weathered quartz-bearing rock fragment
Indeterminate granitic or quartz-rich silicate rock; chiefly quartz (SiO₂), possibly feldspar
igneous
Chert / Flint
Chert (varieties include Flint)
Sedimentary
Dark river-worn cobble, possibly basalt or fine-grained volcanic rock
Likely basaltic rock; exact identification requires a fresh surface and tests
igneous
Turtle Stone / Septarian Nodule (Water-worn)
Septarian Concretion
sedimentary