Dark rounded pebble
Likely basalt or another fine-grained mafic volcanic rock; exact identification is uncertain from the image
igneous
Category
Sedimentary Or Metamorphic (Base Substrate)
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
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Navajo Sandstone
Quartz arenite, predominantly SiO₂ (quartz) with iron-oxide cement
sedimentary
Laterite
Laterite (Iron/Aluminum-rich oxide)
sedimentary
Amethyst and Calcite collection
Silicon Dioxide (SiO2) and Calcium Carbonate (CaCO3)
mineral
Aura Quartz Bead
Silicon dioxide (SiO2) with metal coating
mineral with artificial coating
Gneiss
Metamorphic Gneiss
metamorphic
Mixed mineral and rock collection
Predominantly quartz varieties, including amethyst, plus likely calcite, feldspar, mica, and miscellaneous polished stones
mineral
Mica
Mica group (often Muscovite or Biotite)
mineral
Quartz with Iron Staining
SiO2 with Fe oxide impurities
mineral
Banded Gneiss
Metamorphic Gneiss
metamorphic
Quartzite Pebble
Quartzite (SiO2 based)
metamorphic
Limonite or Goethite (Ironstone)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
mineral
White Agate / Chalcedony
Silicon Dioxide (SiO2)
gemstone
Small red-brown mineral or rock fragment
Unidentified; possibly iron-oxide-rich jasper, garnet, or weathered sulfide
mineral
Light-colored pebble, likely quartzite or weathered limestone
Indeterminate from image; possible quartzite (microcrystalline SiO₂)
metamorphic
Gravel (Crushed Stone Aggregates)
Mixed Siliciclastic / Carbonate Aggregate
sedimentary
Painted River Rock
Artificially Coated Sedimentary Rock
sedimentary
Pumice
Highly vesicular volcanic glass, commonly rhyolitic or andesitic in composition
igneous
Basalt River Stone
Basalt (Mafic volcanic rock)
igneous
Small white mineral fragment
Likely quartz (SiO₂), possibly calcite (CaCO₃)
mineral
Limonite (Iron Ore)
Limonite (FeO(OH)·nH2O)
mineral
Anthracite Coal
Anthracite (Carbon based)
metamorphic
Mica (Muscovite or Biotite)
Sheet silicate mineral group (e.g., KAl2(AlSi3O10)(F,OH)2)
mineral
Limonite (Iron Ore)
FeO(OH)·nH2O (Hydrous ferric oxide)
mineral
River Stone (Basalt or Siltstone)
Basalt (extrusive igneous rock) or fine-grained Siltstone
igneous
Granite Pebble (River Rock)
Phaneritic Felsic Igneous Rock
igneous
Sandstone (Quartzose Pebble)
Clastic Sedimentary Rock (Litharenite/Quartz arenite)
sedimentary
River Pebble (Grantoid/Quartzite)
Quartz-rich igneous rock (Granitoid)
igneous
Lava Rock (Basaltic Scoria)
Vesicular Basalt
igneous
Mixed collection of common river stones
Varied lithologies, visibly including quartz-rich rock, dark mafic rock, sandstone, and purple quartz-bearing material
igneous, sedimentary, metamorphic
Quartzite (or Chert/Flint gravel)
Quartzite (SiO2 with iron oxide inclusions)
metamorphic
Carnelian
SiO2 (Silicon Dioxide with Iron Oxide impurities)
gemstone
Chalcedony (Agate) Pebble
Silicon Dioxide (SiO2)
mineral
Gneiss
Gneiss (Metamorphic Rock)
metamorphic
Clear quartz crystals
Quartz (silicon dioxide, SiO₂)
mineral
![Fossilized bone fragment (probable mammalian tooth or bone) (Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite) — fossil](https://media.rock.id/fossilized-bone-fragment-probable-6435bbec-570b-407e-9c9f-870b904b8d23-thumbnail.jpg)
Fossilized bone fragment (probable mammalian tooth or bone)
Mineralized bone, commonly hydroxyapatite [Ca5(PO4)3(OH)] replaced or impregnated by silica/calcite
fossil
Green Fluorite
Fluorite (Calcium Fluoride, CaF2)
mineral
Pink Quartzite Pebble
Quartzite (SiO2)
metamorphic
Gneiss
Metamorphic Gneiss
metamorphic
Gneiss (Metamorphic Pebble)
Metamorphic Rock (Quartz-Feldspar-Biotite Gneiss)
metamorphic
Quartz-rich limestone or calcitic marble
Calcite (CaCO₃), possibly with quartz (SiO₂)
metamorphic
Small weathered mineral/rock fragment
Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen
mineral