Rock (Likely Sedimentary)

Pebble (likely Siltstone or fine-grained Sandstone)

Sedimentary Clastic Rock

River Cobble (Quartzite or Sandstone)

Clastic sedimentary rock (primarily SiO2)

Chert (Jasper variation)

Microcrystalline Quartz (SiO2)

Sandstone (likely Fossiliferous)

Arenite / Sedimentum arenaceum

Sandstone (likely Ferruginous)

Arenite (SiO2 based with Fe2O3/FeO(OH) cement)

Chert (Pebble)

Microcrystalline silica (SiO2)

Pyritic Gneiss

Metamorphic Gneiss with Pyrite inclusions

Weathered sandstone (probable)

Quartz-rich sandstone, largely composed of cemented quartz grains (SiO₂)

Foliated metamorphic rock, likely biotite schist

Mica schist, chiefly quartz, feldspar, and biotite mica

Sandstone (Greywacke)

Arenite / Greywacke Sandstone

Red Sandstone Pebble

Arenite with iron oxide (Hematite)

Sandstone (likely Quartz Sandstone)

Arenite (composed primarily of SiO2)

Fossiliferous Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Conglomerate

Conglomerate (clastic sedimentary rock)

Geode (Unopened)

Siliceous Septarian Concretion / Geode (SiO2)

Likely weathered quartz-rich stone or fossil fragment

Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil

Chert Nodule (Commonly known as Flint or River Rock)

Silicon Dioxide (SiO2)

Sandstone (likely Arkose or Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Fossiliferous Limestone

Calcite (CaCO3) Rich Bio-sedimentary Rock

Sandstone

Arenite (primarily SiO2)

Conglomeratic breccia

Clast-supported polymictic conglomerate/breccia, cemented by silica- or carbonate-rich matrix

Unknown Tumbled Stone

Unknown (Too Blurry)

Rounded gray-brown river pebble

Indeterminate lithic clast; likely weathered sandstone or fine-grained metamorphic rock

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with feldspar, mica, and iron-oxide impurities

Chert (often called Jasper or River Siltstone)

Microcrystalline Quartz (SiO2)

Chert (often called Jasper or River Siltstone)

Microcrystalline Quartz (SiO2)

Fossiliferous Limestone with Crinoid Stem fragment

Calcite (CaCO3) containing Crinoidea fossils

Quartz Vein in Host Rock (likely Sandstone or Mudstone)

Silicon Dioxide (SiO2) within Sedimentary Matrix

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Ferruginous Chert

Microcrystalline Quartz (SiO2) with Iron Oxides

Quartzite pebble with Mafic inclusions

Quartzite (SiO2)

Jasper (with Agate/Chalcedony inclusions)

Silicon Dioxide (SiO2)

Quartz Geodes and Crystal Clusters

Silicon Dioxide (SiO2)

Weathered mafic rock, likely basalt

Basalt; primarily plagioclase feldspar, clinopyroxene, and commonly olivine or magnetite

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 predominantly)

Sandstone (likely Graywacke or Siltstone variety)

Clastic Sedimentary Rock (SiO2 with assorted mineral fragments)

Chert (Flint) Pebble

Microcrystalline Quartz (SiO2)

Sandstone (Weathered Cobble)

Clastic Sedimentary Rock (primarily SiO2)

Quartzite with Chert inclusions

Metamorphosed Quartz-rich Rock (SiO2)

André's Landing Rock (Sandstone Boulder)

Newark Supergroup Sandstone (likely Stockton Formation)

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)

Travertine (Ceramic Tile)

Terrestrial Sedimentary Rock / Calcium Carbonate (CaCO3)