River Pebble
Weathered Sedimentary Rock Fragment
Category
Browse sedimentary or metamorphic (base substrate) specimens identified by the Rock Identifier community.
River Pebble
Weathered Sedimentary Rock Fragment
Sapphire
Corundum (Al2O3)
Yellow Jasper (Chert variant)
Silicon Dioxide (SiO2) with iron oxide inclusions
Expanded Clay Pebble
Lightweight Expanded Clay Aggregate (LECA)
Quartz Pebble
Silicon Dioxide (SiO2)
River Pebble (Siltstone / Sandstone Pebble)
Sedimentary Rock (Quartz, Feldspar, Clay Minerals)
Sandstone
Arenite
Fossiliferous Limestone (Coral Rag)
Biogenic Limestone (Calcium Carbonate, CaCO3)
White Quartz Pebble
Silicon Dioxide (SiO2)
Quartz pebble
Silicon dioxide (SiO2)
Quartz Pebble
Silicon dioxide (SiO2)
Gravel / Small Pebble
Rock Fragment (Gravel)
River Pebble / Chert Pebble
Microcrystalline Quartz (SiO2)
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
Quartzite Pebble
Quartzite (SiO2)
Quartzite Pebble
Metamorphosed Sandstone (SiO2)
Quartzite Pebble
Quartzite (primarily SiO2)
Quartz Vein in Pelite (Metamorphic Rock)
Hydrothermal Quartz Veining in Metasedimentary Rock (SiO2)
Moss-covered Rock Fragment
Weathered Rock Fragment with Epilithic Growth
Tufa
Calcareous Tufa (Calcium Carbonate, CaCO3)
Jasper pebble
Silicon Dioxide (SiO2) with impurities
River Stone (Basalt or Siltstone)
Mafic Volcanic Rock or Clastic Sedimentary Rock
Fossilized Bored Limestone
Limestone with Ichnofossils (Gastrochaenolites or Entobia)
Tiger's Eye
Silicon dioxide (SiO2) - Pseudomorph after crocidolite
Mixed river stones and gravel
Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate
Agate
Silicon Dioxide (Chalcedony), SiO2
Agate
Chalcedony (SiO2)
River Stone (Limestone)
Sedimentary Calcium Carbonate (CaCO3)
River Stones (Basalt and Sedimentary Rock)
Basalt (dark specimen) and Siltstone/Mudstone (reddish specimen)
Aragonite (Sputnik habit)
Aragonite (Calcium Carbonate, CaCO3)
Zoisite with Hornblende
Zoisite (Ca2Al3(SiO4)3(OH)) with Amphibole inclusions
Agate
SiO2 (Chalcedony/Quartz)
Sandstone (River Pebble)
Clastic Sedimentary Rock (primarily Quartzite/Arenite)
Oolitic Limestone (Egg Stone)
Oolite (Chemical sedimentary rock, primarily CaCO3)
Black River Stone (Chert or Basalt Pebble)
Microcrystalline Quartz (SiO2) or Mafic Igneous Rock
Tufa
Calcareous Tufa (CaCO3)
Druzy Quartz
Silicon Dioxide (SiO2)
Druzy Quartz (on Geode Fragment)
Silicon Dioxide (SiO2)
Blue Sapphire
Corundum (Al2O3 with trace Titanium and Iron)
Mossy Rock
Mixed lithology rock with Bryophyta (moss)
Chalcedony (Tumbled Pebble)
Silicon Dioxide (SiO2)
Jasper
Silicon dioxide (SiO2) with impurities