Tumbled yellow jasper (probable)
Jasper, an opaque microcrystalline variety of quartz; chiefly SiO₂ with iron-oxide inclusions
mineral
Category
Rock
Browse rock specimens identified by the Rock Identifier community.
Vesicular Basalt (or Scoria)
Vesicular Basalt
igneous
Shale / Mudstone
Laminated Mudrock (Siliciclastic Sedimentary Rock)
sedimentary
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4
metamorphic
Agate Geode
Silicon Dioxide (SiO2) - Chalcedony variety
sedimentary
Tumbled serpentine with dark magnetite/chromite matrix
Serpentinite; chiefly antigorite/lizardite, Mg3Si2O5(OH)4, with magnetite and possibly chromite
metamorphic
Basalt
Basalt
igneous
Gneiss
High-grade regional metamorphic rock (Foliated)
metamorphic
Granite
Granite (Phaneritic intrusive igneous rock)
igneous
Basalt
Basalt
igneous
Shale (Beach-worn)
Laminated Pelite (primarily clay minerals and quartz)
sedimentary
River-worn Chert
Microcrystalline Quartz (SiO2)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Quartz Pebble (Feldspathic / Chert Pebble)
Silicon Dioxide (SiO2) / Potassium Feldspar (KAlSi3O8)
sedimentary
Sandstone (River Cobble)
Sandstone (principally composed of Quartz, SiO2)
sedimentary
Quartz Geode
Silicon Dioxide (SiO2) within a sedimentary or volcanic shell
mineral
Quartz Geode
Silicon Dioxide (SiO2)
mineral
Yellow Agate (Banded Chalcedony)
Silicon Dioxide (SiO2)
sedimentary
Unknown Tumbled Stone
Unknown (Too Blurry)
mineral
Rounded gray river cobble, likely quartz-rich sandstone or weathered granite
Indeterminate; possible granitic or feldspathic cobble (quartz–feldspar–mica aggregate)
igneous
Granite (likely weathered biotite granite)
Felsic intrusive igneous rock; mainly quartz, potassium feldspar, plagioclase, and biotite mica
igneous
Weathered granite or granitic gneiss pebble
Granite; primarily quartz, potassium feldspar, plagioclase, and mica
igneous
Likely gneiss
Gneiss, composed chiefly of quartz, feldspar, and mica/amphibole
metamorphic
Amber-bearing Coal/Sedimentary Rock
Bituminous coal or carbonaceous siltstone with Fossilized Tree Resin (C10H16O)
sedimentary
Desert Rose (Gypsum Rose)
Calcium Sulfate Dihydrate (CaSO4·2H2O)
mineral
Weathered greenstone pebble (probable serpentinite or altered basalt)
Serpentinite-group rock, commonly dominated by antigorite/lizardite; identification is uncertain from the photograph
metamorphic
Orange Quartz (or Carnelian Chalcedony)
Silicon Dioxide (SiO2)
mineral
Basalt with Quartz Vein
Extrusive Igneous Rock / Volcanic Rock
igneous
Porphyritic Basalt or Porphyritic Andesite
Porphyritic Extrusive Igneous Rock
igneous
Likely weathered granite or granitic pegmatite fragment
Granite; primarily quartz (SiO₂), feldspar, and mica
igneous
Weathered porphyritic volcanic rock (likely basaltic andesite)
Porphyritic basaltic andesite; mineral assemblage likely plagioclase, pyroxene, and iron oxides
igneous
Herkimer Diamond
Quartz (Silica - SiO2)
mineral
Granite pebble
Granite; chiefly quartz, feldspar, and mica
igneous
Quartz-Veined Slate or Greenstone
Metamorphic rock with quartz vein (SiO2)
metamorphic
Weathered granite or granitic gneiss
Granite: quartz, feldspar, and mica; possibly gneiss if the dark minerals are banded
igneous
Granite
Granite; primarily quartz (SiO₂), feldspar, and mica
igneous
Weathered quartz-rich pebble
Likely milky quartz (SiO₂), possibly a quartz-rich vein fragment
mineral
Sandstone (Weathered Cobble)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Desert Varnish on Sandstone
Ferromanganese coating on Quartz Arenite
sedimentary
Vesicular Basalt (Scoria)
Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)
igneous
Quartzite with Feldspar and Mica (Granitic Gneiss Pebble)
Metamorphic Rock / Quartzite / Granitic Gneiss
metamorphic
Sandstone Pebble
Sandstone (Silicon dioxide-rich clastic sedimentary rock)
sedimentary