River/Stream Pebble
Clast / Detrital Grain / Rounded Sedimentary Particle (Compositionally variable, commonly Quartz, Feldspar, Chert, or other resistant rock fragments)
Mineral, specifically a rock fragment
Category
Mineral, Specifically A Detrital Grain
Browse mineral, specifically a detrital grain specimens identified by the Rock Identifier community.
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Conglomerate
Conglomerate (Detrital sedimentary rock)
sedimentary
Unidentifiable Rock Fragment
Uncertain
Schorl (Black Tourmaline)
Sodium Iron Aluminum Borosilicate (NaFe3Al6(BO3)3Si6O18(OH)4)
mineral
Feldspar (Potassium Feldspar / Orthoclase)
KAlSi3O8 (Potassium Aluminum Silicate)
mineral
Granitic Sand
Detrital sediment (predominantly Quartz, Feldspar, and Mica)
sedimentary
Chert (specifically Tan Chert)
Chert (SiO2)
sedimentary
Magnetite
Iron(II,III) oxide (Fe3O4)
mineral
Black Tourmaline (Schorl)
Schorl (Na(Fe^2+)3Al6(Si6O18)(BO3)3(OH)4)
Mineral
Coarse Sand or Fine Gravel
Detrital Sedimentary Fragments (mostly SiO2)
sedimentary
Moqui Marble (Shaman Stone)
Ironstone Concretion (Iron oxide Fe2O3 and FeO(OH))
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
sedimentary
Mica / Muscovite or Biotite
Phyllosilicate mineral group (e.g., KAl2(AlSi3O10)(OH)2)
mineral
Siltstone
Siltstone (Detrital Clastic Sedimentary Rock)
sedimentary
Pebble
Lithic fragment / Water-worn rock
sedimentary
Glauconitic Sandstone (Greensand)
Glauconite (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2
sedimentary
Ironstone Concretion (Moqui Marble)
Iron-oxide Concretion (Hydrated ferric oxide, Fe2O3·nH2O)
sedimentary
Quartz / Chalcedony Pebble
Silicon Dioxide (SiO2)
sedimentary
Agate (specifically Carnelian or Honey Agate)
Silicon Dioxide (SiO2)
Mineral
Quartz
Silicon Dioxide (SiO2)
Mineral
Gravel
Unconsolidated rock fragments / detrital sediment
sedimentary
Yellow Jasper / Chert
Silicon Dioxide (SiO2) with Goethite or Limonite inclusions
sedimentary
Granitic Pegmatite
Granite Pegmatite (coarse-grained intrusive igneous rock)
igneous
Quartz (Small Pebble)
Silicon Dioxide (SiO2)
mineral
Gravel or Pebble
Clastic Sedimentary Grain (typically composed of Quartz or Silicate minerals)
sedimentary
River Gravel
Polymictic Gravel / Detrital Rock Aggregate
sedimentary
Amber (Burmite)
Fossilized tree resin (Succinite variant)
Organic mineraloid
Potassium Feldspar
Orthoclase (KAlSi3O8)
mineral
Gravel and Pavement Aggregates
Unconsolidated rock fragments / detrital sediments
sedimentary
Brown Antique Granite
Anorthosite (Technically a plutonic rock composed mainly of plagioclase feldspar)
igneous
Labradorite (a variety of Feldspar)
Labradorite; (Na,Ca)(Al,Si)4O8 (a plagioclase feldspar)
igneous
Gravel and Pebbles
Unconsolidated rock fragments / detrital sediment
sedimentary
K2 Jasper (K2 Stone)
Azurite in Granite / Quartzite
metamorphic
Sandstone (Ferruginous)
Arenite (with Iron Oxide cement)
sedimentary
Pink Granite
Phaneritic Felsic Igneous Rock
igneous
Porphyritic Rhyolite
Porphyritic Rhyolite (SiO2)
igneous
Gravel and River Pebbles
Unconsolidated rock fragments / Detrital sediment
sedimentary
Diabase
Diabase (also known as Dolerite)
igneous
Rose Quartz
Silicon dioxide (SiO2)
mineral
Pink Granite
Granite (Phaneritic Quartz-Feldspar rock)
igneous
Magnetite
Magnetite (Fe3O4)
Mineral
Porphyry (specifically Porphyritic Rhyolite or Andesite)
Porphyritic Igneous Rock (composed of Phenocrysts in an Aphanitic groundmass)
igneous