Not A Rock (Synthetic Material)

Weathered volcanic rock, likely vesicular basalt or scoria

Basaltic volcanic rock; predominantly plagioclase, pyroxene, and possibly olivine with iron-oxide weathering

Chondrite Meteorite

Ordinary Chondrite (OC)

Weathered granite pebble

Granite, chiefly quartz (SiO₂), feldspar, and mica/amphibole

Mookaite Jasper

Silicified Radiolarite (Silicon Dioxide: SiO2)

Weathered granitic rock, likely granodiorite

Granodiorite: quartz, plagioclase feldspar, potassium feldspar, and biotite/hornblende

Aventurine

Aventurine Quartz (SiO2 with inclusions)

Brecciated jasper/chalcedony (iron-stained silica)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (River Pebble)

Silicon Dioxide (SiO2)

Conglomerate

Conglomerate

Quartzite Pebble with Pyrite Coating

SiO2 (Quartz) with FeS2 (Pyrite) inclusions or surface coating

Tree Agate (or Moss Agate)

Dendritic Agate (Silicon Dioxide - SiO2)

Quartzite

Quartzite (Recrystallized Quartz Sandstone)

Mica Schist

Mica Schist (Schistose metamorphic rock rich in Muscovite/Biotite)

Possible basaltic rock or meteorite candidate

Likely vesicular basalt; meteorite identification cannot be confirmed visually

Serpentine

Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Crushed Granite Gravel

Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase Feldspar)

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–mica rock; chiefly quartz (SiO₂), feldspars, and biotite mica

Likely chert or flint

Microcrystalline quartz (SiO₂), commonly called chert; exact identification requires testing

Basalt

Basalt (Mafic volcanic rock)

Diorite (with Iron Staining)

Phaneritic Intermediate Igneous Rock

Quartz Arenite / Sandstone

Quartz sandstone (SiO2 rich clastic sedimentary rock)

Quartzite

Quartzite (primarily SiO2)

Shale or Mudstone (Based on appearance)

Shale (fine-grained, laminated fissile sedimentary rock) / Mudstone (fine-grained, non-fissile sedimentary rock)

Sandstone with Calcite Vein

Clastic sedimentary rock (primarily SiO2) with Calcium Carbonate (CaCO3) infilling

Weathered brown mineralized rock

Likely iron-stained quartzite or quartz-rich metamorphic rock; exact identification requires testing

Chert (Jasper variation)

Silicon Dioxide (SiO2)

Banded gneiss

Gneiss; chiefly quartz, feldspar, and mica

Chert (Nodule)

Silicon Dioxide (SiO2)

Granite

Granite (Phaneritic intrusive igneous rock)

Fossilized Wood (Petrified Wood)

Agatized wood (primarily SiO2)

Chert (Flint / Agate Nodule)

Silicon Dioxide (SiO2)

Ferruginous Conglomerate

Conglomerate with Iron-Oxide Matrix (SiO2 + Fe2O3/FeO(OH))

River Rock (Quartzite/Chert conglomerate)

Quartzite (SiO2)

Unakite

Epidote–K-feldspar–quartz granitoid (often called unakite)

Jasper Breccia

Brecciated Jasper (Silicon Dioxide with Iron Oxide inclusions, SiO2)

Dark basalt fragment

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase and pyroxene, commonly with olivine

Sandstone (Ferruginous/Banded)

Clastic Terrigenous Sandstone (SiO2 with Fe2O3 cement)

Basalt

Basalt

Diorite (Spotted or Dalmatian Stone pattern)

Diorite

Sandstone with Iron Oxide

Arenite (SiO2 with Fe2O3 inclusions)

Quartz (specifically Milky or Clear Chunk)

Silicon Dioxide (SiO2)