Synthetic Material (Not A Rock Or Mineral)

Quartzite

Quartzite (SiO2)

Sandstone (Banded)

Clastic sedimentary rock (primarily SiO2)

Sandstone (Weathered Pebble)

Arenite (primarily SiO2)

Concrete Fragment

Hardened Portland Cement Composite

Quartz Pebble

Silicon Dioxide (SiO2)

Brecciated jasper/chert

Microcrystalline quartz (SiO₂), with iron-oxide and clay inclusions

Sandstone (Quartzite-leaning)

Arenite (primarily SiO2)

Breccia

Breccia

Tumbled blue-green stone, likely chrysocolla-bearing jasper

Chrysocolla-rich chalcedony/jasper; commonly a mixture of chrysocolla (hydrated copper silicate, variable formula) and quartz (SiO₂)

Garnet-bearing gneiss

Quartz–feldspar–mica gneiss with iron-rich garnet (commonly almandine)

Sandstone (with Feldspathic/Arkose qualities)

Arenite (primarily SiO2 with KAlSi3O8 components)

Granite Boulder

Felsic Intrusive Igneous Rock

Unidentifiable Rock Fragment

Sandstone (specifically Red Sandstone)

Arenite (SiO2 with Iron Oxide)

Sandstone (Red)

Arenite (primarily SiO2 with Iron Oxide staining)

Shale or Slate with Quartz Veins

Shale (fine-grained clastic sedimentary rock) or Slate (low-grade metamorphic rock formed from shale) with Quartz (SiO2) veins

Bivalve Fossil (Clam)

Class Bivalvia, likely Mercenaria or similar genus

Biotite Mica in Host Rock

Biotite (K(Mg,Fe)3AlSi3O10(F,OH)2)

Greywacke (Sandstone)

Lithic wacke

Greenschist

Greenschist facies rock

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Red Sandstone

Arenite (predominantly SiO2 with Fe2O3 staining)

Chert (River Pebble)

Microcrystalline Quartz (SiO2)

Tumbled basalt (likely)

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine

Porphyritic Basalt

Basalt (Mafic Extrusive Igneous Rock)

Weathered basaltic rock fragment

Basalt, likely porphyritic or amygdaloidal basalt with weathered iron-oxide-rich zones

Turritella Fossil

Turritella (Class Gastropoda, Family Turritellidae)

Banded Gneiss (River Cobble)

Gneiss (a high-grade metamorphic rock)

Diorite

Intermediate Phaneritic Igneous Rock

Blue Quartzite (Dyed)

Metamorphosed Quartz-rich Sandstone (SiO2 with organic dye)

Diorite

Diorite (intermediate plutonic rock)

Ferruginous Sandstone

Ferruginous Quartz-Arenite

Honey-colored chalcedony (possibly yellow/orange agate or carnelian)

Chalcedony, a microcrystalline variety of quartz; SiO₂. The color may result from iron-oxide inclusions. Exact identification is uncertain from a photograph alone.

Conglomerate

Clastic sedimentary rock (Conglomerate)

Polished orbicular jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with hematite/goethite and other silicate inclusions

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Ferruginous Sandstone (Ironstone)

Arenite with Limonite/Goethite cement

Quartz-rich granite or pegmatitic rock

Granite/pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica

Fossilized cylindrical shell or bone fragment

Indeterminate biogenic carbonate or phosphatic fossil; possible fragment of a tubular shell (e.g., scaphopod) or hollow bone

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

Red Sandstone

Arenite with Hematite (Fe2O3)