Not A Rock (Synthetic Material)

Sandstone

Arenite (SiO2 primarily)

Calcite (or Alabaster, if truly carved)

Calcium Carbonate (CaCO3)

Biotite (Mica)

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

Red Sandstone

Arenite (Ferruginous Sandstone)

Chert (often called Flint when dark)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Blue Apatite

Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)

Nuummite

Orthoamphibole (Anthophyllite-Gedrite composition)

Quartzite Pebble

Quartzite (mostly SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Siltstone Pebble

Siltstone

Quartzite Pebble

Quartzite (SiO2)

Banded Chert

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Kyanite

Kyanite (Al2SiO5)

Milky Quartz

Silicon Dioxide (SiO2)

Sunstone

Oligoclase (a variety of Plagioclase Feldspar) - (Na,Ca)(Si,Al)4O8

Coquina

Bioclastic Limestone

Chert / Flint

Silicon Dioxide (SiO2)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Pyrite Geode

Iron Disulfide (FeS2)

Chalcedony (Agate)

Silicon Dioxide (SiO2)

Peridot (Olivine)

Olivine ((Mg, Fe)2SiO4)

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily Chalcedony or Quartz, SiO2)

Chert (Flint)

Chert (SiO2)

Stichtite in Serpentine (Atlantasite)

Mg6Cr2CO3(OH)16·4H2O in Mg3Si2O5(OH)4

Milky Quartz

Silicon Dioxide (SiO2)

Siltstone

Siltstone (primarily composed of SiO2 with various clay minerals)

Banded Chert

Silicon Dioxide (SiO2)

Agate (Nodule/Chert)

Silicon Dioxide (SiO2)

Chert Breccia

Brecciated Chert (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Milky Quartz

Silicon Dioxide (SiO2)

Polygenetic Conglomerate (Puddingstone)

Conglomerate (SiO2 matrix with mixed clasts)

Quartzite

Quartzite (SiO2)

Siltstone with Weathering Rind

Siltstone (composed of microscopic quartz and clay minerals)

Chert (Jasper)

Silicon dioxide (SiO2)

Chert Pebble

Microcrystalline Quartz (SiO2)

Chert (Arrowhead Artifact)

Chert (SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Iron Meteorite

Siderite (Iron-Nickel Meteorite)