Chalcedony Geode Fragment
Microcrystalline Quartz (SiO2)
Category
Browse sedimentary or igneous fragment specimens identified by the Rock Identifier community.
Chalcedony Geode Fragment
Microcrystalline Quartz (SiO2)
Generic Pebble / Rock Fragment
Lithic fragment / Weathered rock
Quartz Drusy (on Geode Fragment)
Crystalline Silicon Dioxide (SiO2)
Quartz (White/Milky)
Silicon Dioxide (SiO2)
Quartz Crystal Fragment
Silicon Dioxide (SiO2)
Rock crystal quartz fragment
Quartz (silicon dioxide, SiO₂)
Fragmented Sedimentary Pebble
Clastic Sedimentary Specimen
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
Red Jasper
Silicon Dioxide (SiO2) with iron oxide inclusions
Chert (Flint)
Cryptocrystalline Quartz (SiO2)
Generic Rock Fragment
Rock Fragment
Banded Agate (with small Geode cavity)
Silicon Dioxide (SiO2) - Chalcedony variety
Concrete fragment or Conglomerate
Artificial Conglomerate (Concrete) or Natural Conglomerate
Gneiss
Gneissic Metamorphic Rock
Coarse Sand or Fine Gravel
Detrital Sedimentary Fragments (mostly SiO2)
Likely quartz crystal fragment
Quartz (SiO₂), possibly a small tumbled or cleaved fragment
Red Garnet (likely Almandine or Pyrope)
Garnet group: X3Y2(SiO4)3 (e.g., Almandine: Fe3Al2Si3O12)
Opal
Hydrated Silica (SiO2·nH2O)
Granite fragment
Granite
Milky quartz (quartz-rich fragment)
Quartz, silicon dioxide (SiO₂)
Quartz-veined Metamorphic Pebble
Silicate-rich metamorphic rock with quartz veins (SiO2)
Weathered quartz-rich stone, possibly chalcedony or calcite
Likely microcrystalline quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing
Likely weathered quartz-rich stone
Probably quartz-bearing sandstone or milky quartz; exact identification requires testing
River Pebble
Weathered Sedimentary Rock Fragment
Waterworn Pebble / Quartzite
Metamorphic/Sedimentary rock fragment
Pebble
Lithic fragment / Sedimentary clast
Geode
Silicon Dioxide (Quartz/Chalcedony) in carbonate or volcanic host rock
Dark metamorphic rock, likely biotite schist or gneiss
Quartz–feldspar–biotite metamorphic rock; exact identification requires a fresh surface and testing
Gneiss
Gneiss
Quartz
Silicon Dioxide (SiO2)
Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Druzy Quartz (on Geode Fragment)
Silicon Dioxide (SiO2)
Quartz (Milky or Clear fragment)
Silicon Dioxide (SiO2)
Quartz (Milky/Crystalline fragment)
Silicon Dioxide (SiO2)
Chert (Flint)
Chert (Microcrystalline or cryptocrystalline Quartz - SiO2)
Sandstone (with garnet granules)
Clastic sedimentary rock (primarily SiO2 with Fe3Al2(SiO4)3 inclusions)
Pebble
Clast (specifically a granule or small pebble)
Shale fragment
Shale (clay mineral rich sedimentary rock)
Quartz Geode Fragment
Silicon Dioxide (SiO2)
Fossil shell fragment
Indeterminate molluscan bioclast, likely aragonite or calcite
Banded Gneiss Pebble
Gneiss (Metamorphic Rock)
Sand and Gravel (Quartz-rich)
Unconsolidated fluvial/beach sediment (primarily Silica/SiO2)