Not A Rock (Synthetic Material)

Chert (specifically Gray Chert)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Sandstone

Arenite (primarily SiO2 with various cementing agents)

Serpentinite

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

Shale (with Iron Oxide staining)

Fissile Mudstone (primarily Quartz and Clay minerals)

Sandstone (Ferruginous)

Arenite with Iron Oxide cement

Dalmation Stone (Dalmation Jasper)

Peralkaline rock (primarily Feldspar and Quartz with Arfvedsonite spots)

Sandstone (Quartz Arenite)

Sandstone (Chemical formula: primarily SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Decomposed Granite

Grano-diorite/Granite-residuum (SiO2 primary)

Sandstone (Red/Brown Variety)

Arenite (composed primarily of SiO2 with Fe2O3 iron oxide inclusions)

Asphalt (Bituminous Slate/Sandstone)

Asphaltum / Bituminous Rock

Basalt (Weathered)

Extrusive Igneous Rock (Mafic composition)

Riverstone Quartzite

Quartzite (primarily SiO2)

Chert (potentially Flint or Mudstone)

Microcrystalline Quartz (SiO2)

Biotite Schist

Biotite Schist (Rich in K(Mg,Fe)3AlSi3O10(OH)2)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Mica Schist with Garnet

Garnetiferous Mica Schist

Sandstone

Arenite (composed primarily of SiO2)

Basalt (Vesicular/Scoria)

Vesicular Basalt

Basalt

Basalt (Aphanitic Mafic Igneous Rock)

Red Jasper (Quartz)

Silicon Dioxide (SiO2) with Iron impurities

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Sandstone (Ferruginous)

Arenite with Iron Oxide (Fe2O3) cement

Amygdaloidal Basalt with Epidote

Vesicular Basalt with secondary Epidote/Quartz mineral infill

Olivine in Basalt matrix

Peridotite (Mg, Fe)2SiO4

Caliche (with Lichen Cover)

Calcium carbonate-cemented soil layer (CaCO3)

Travertine (Calcareous Tufa)

Calcium Carbonate (CaCO3)

Chert Nodule (Commonly known as Flint or River Rock)

Silicon Dioxide (SiO2)

Andesite

Andesite (Intermediate Extrusive Volcanic Rock)

Scoria (Basaltic Lava Rock)

Vesicular Basalt

Sandstone

Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)

Dalmatian Jasper

Dalmatian Stone (a microcrystalline quartz and feldspar rock with arfvedsonite)

Sandstone (likely Red/Brown Sandstone)

Arenite (SiO2 based)

Limestone

Calcium Carbonate (CaCO3)

River Stone (Quartzite/Siltstone mixture)

Silicon Dioxide (SiO2) based metamorphosed sandstone

Gneiss (Banded Gneiss)

Gneiss

Phyllite

Phyllite (Foliated metamorphic rock)

Granodiorite

Granodiorite (containing Plagioclase, Quartz, and Biotite)

Travertine

Calcareous Tufa / Travertine (CaCO3)

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (primarily SiO2)

Porphyritic Basalt (Chinese Writing Stone or Flower Stone)

Porphyritic Basalt / Porphyry