Gravel / Small Pebble
Rock Fragment (Gravel)
Category
Browse biogenic material specimens identified by the Rock Identifier community.
Gravel / Small Pebble
Rock Fragment (Gravel)
Sandstone
Sandstone (SiO2 with iron oxides and clay)
Pebble / Rounded Rock
Lithic fragment / Water-worn rock
Sandstone (Pebble / Cobble)
Arenite / Sedimentary Rock (composed of quartz and feldspar)
Quartz (Iron-Stained / Yellow Quartz)
Silicon Dioxide (SiO2)
Chiastolite
Andalusite variety Chiastolite
Thunderegg (Agate or Quartz Geode)
Silica-filled rhyolitic nodule (SiO2)
Sandstone
Arenite
Sandstone
Arenite (SiO2 primarily)
Potassium-Rich Silicate Clay (inferred from biological context)
Phyllosilicate group (likely Illite or Smectite within surrounding soil substrate)
Sandstone
Arenite (SiO2 primarily)
Sedimentary Sandstone (Sandstone Slab)
Arenite (SiO2 with Fe2O3 staining)
Chert (Flint)
Silicon Dioxide (SiO2)
Sandstone
Arenite
Sandstone
Clastic sedimentary rock (primarily SiO2)
Sandstone (with Iron Staining)
Clastic sedimentary rock (primarily Quartz with Limonite/Goethite staining)
Sandstone
Arenite (composed primarily of SiO2)
Chert (often called Flint when found in chalk)
Microcrystalline Quartz (SiO2)
Quartz
Silicon Dioxide (SiO2)
Tumbled agate (probable moss or dendritic agate)
Microcrystalline quartz, SiO₂, with iron/manganese dendritic inclusions
Slate
Metamorphic Pelitic Rock
Chert (Flint)
Microcrystalline quartz (SiO2)
Rough Diamond
Carbon (C)
Chert
Microcrystalline Quartz (SiO2)
Chert (Flint) with Glauconite
Microcrystalline Quartz (SiO2)
Chert
Microcrystalline Quartz (SiO2)
Caliche (with Lichen Cover)
Calcium carbonate-cemented soil layer (CaCO3)
Aggregate Concrete
Anthropogenic Conglomerate (Technosol)
Milky quartz (massive quartz)
Quartz, silicon dioxide (SiO₂)
Chert
Microcrystalline Quartz (SiO2)
Likely basalt with a pale mineral-filled vesicle
Vesicular basalt, probably containing calcite or zeolite (uncertain from image)
Travertine
Calcium Carbonate (CaCO3)
Tiger's Eye
Silicon Dioxide (Quartz with crocidolite inclusions), SiO2
Blue Apatite
Ca5(PO4)3(F,Cl,OH)
Diamond
C
Chert (Flint)
Microcrystalline Quartz (SiO2)
Chert / Flint
Silicon dioxide (SiO2)
Diamond (or Cubic Zirconia)
Cubic Carbon (C) or Zirconium Dioxide (ZrO2)
Muscovite Mica
Muscovite (Potassium Aluminum Silicate Hydroxide), KAl2(AlSi3O10)(OH)2
Chert (Flint)
Silicon Dioxide (SiO2)
Diamond (Set in Jewelry)
Carbon (C)
Banded Chert
Silicon Dioxide (SiO2)