Mixed polished river pebbles, predominantly quartzite and quartz
Quartzite (SiO₂), quartz (SiO₂), with possible feldspar-rich and iron-stained lithologies
metamorphic
Category
Sedimentary Or Metamorphic (Base Substrate)
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
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White marble chips
Marble; predominantly calcite (CaCO₃)
metamorphic
Sandstone (River Pebble)
Clastic Sedimentary Rock (primarily Quartzite/Arenite)
sedimentary
Black River Stone (Chert or Basalt Pebble)
Microcrystalline Quartz (SiO2) or Mafic Igneous Rock
sedimentary
Oolitic Limestone (Egg Stone)
Oolite (Chemical sedimentary rock, primarily CaCO3)
sedimentary
Tufa
Calcareous Tufa (CaCO3)
sedimentary
Variscite
AlPO4·2H2O
mineral
Jasper
SiO2
Mineral
Druzy Quartz (on Geode Fragment)
Silicon Dioxide (SiO2)
mineral
Druzy Quartz
Silicon Dioxide (SiO2)
mineral
River Stones (Basalt and Sedimentary Rock)
Basalt (dark specimen) and Siltstone/Mudstone (reddish specimen)
igneous and sedimentary
Zoisite with Ruby
Anyolite (Calcium aluminum hydroxy silicate with Corundum) Ca2Al3(SiO4)3(OH)
metamorphic
Mixed beach gravel and cobbles
Polylithic alluvial or littoral clasts, including quartz, quartzite, chert, limestone, sandstone, and flint
sedimentary
Sandstone Beach Pebble
Clastic Sandstone (SiO2 - Quartz-dominant)
sedimentary
Blue sapphire (likely synthetic or treated corundum)
Corundum, aluminum oxide (Al₂O₃), blue from iron and titanium impurities
gemstone
White Buffalo Turquoise (or Howlite/Magnesite)
Calcite/Dolomite or Magnesite with Chert/Quartz inclusions
gemstone
Vesicular volcanic rock, likely pumice or scoria
Pumice/scoria; predominantly vesicular volcanic glass and feldspar-rich silicate minerals
igneous
Quartzite River Stone
Metamorphic Quartzite (primarily SiO2)
metamorphic
Gravel / Small Pebble
Rock Fragment (Gravel)
sedimentary
Hand-Drawn Trading Card (Amateur Artwork)
Cellulose-based substrate with wax/graphite/ink deposit (n/a for minerals)
Organic/Synthetic Composite (Paper and Pigment)
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz River Pebble
Silicon Dioxide (SiO2)
mineral
Blue Sapphire
Corundum (Al2O3 with trace Titanium and Iron)
mineral
Amber (likely a small rough amber piece)
Fossilized plant resin; amber is an organic mineraloid, not a crystalline mineral
gemstone
Banded River Cobble (Argillite or Shale)
Laminated Mudstone / Argillite
sedimentary
River Stone (Chert/Siltstone)
Cryptocrystalline Quartz (SiO2) with trace impurities
sedimentary
Red Sandstone (Old Red Sandstone Pebble)
Arenite with iron oxide (Fe2O3) cement
sedimentary
White Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Zoisite with Hornblende
Zoisite (Ca2Al3(SiO4)3(OH)) with Amphibole inclusions
metamorphic
Note: Item is a Synthetic/Man-made Object
Titanium-coated Stainless Steel (Fe-Cr-Ni-Ti)
Non-geological
Schist
Metamorphic Rock (Schist)
metamorphic
Quartzite with Mica / Gneiss Pebble
Metamorphic Rock (Quartz-Feldspar-Mica aggregate)
metamorphic
Rounded gray river cobble
Likely fine-grained sandstone, siltstone, or metamorphosed equivalent; exact identification requires a fresh surface and tests
sedimentary
Fulgurite
Fulgurite (Lechatelierite/Silica glass)
mineral
Vesicular basalt (scoria-like lava rock)
Mafic volcanic rock, typically plagioclase + pyroxene ± olivine; vesicles formed by trapped volcanic gas
igneous
Jasper
Silicon dioxide (SiO2)
sedimentary
Mixed tumbled gravel and quartz-rich sandstone
Primarily quartz (SiO₂), feldspar, and lithic sedimentary fragments; one piece appears to be quartz-rich sandstone
sedimentary
Sandstone (River Pebble)
Quartz Arenite / Lithic Sandstone
sedimentary
Colorless Quartz (Rhinestone)
Silicon Dioxide (SiO2)
mineral
Red Jasper
Silicon Dioxide (SiO2) with Hematite (Fe2O3) inclusions
sedimentary
Gneiss
Gneissic Metamorphic Rock
metamorphic
White Sapphire
Corundum (Al2O3)
mineral