Quartz Pebble (Water-worn Quartzite)

Silicon Dioxide (SiO2)

metamorphic

Quartz (River Pebble)

Silicon Dioxide (SiO2)

mineral

Yellow Quartzite (River Pebble)

Quartzite (SiO2)

metamorphic

Unakite / Epidosite

Epidote with Orthoclase and Quartz; (Ca2(Al2,Fe)(SiO4)3(OH)) / (KAlSi3O8) / (SiO2)

metamorphic

Flint / Chert

Silicon dioxide (SiO2)

sedimentary

Diorite (Salt and Pepper Rock)

Diorite

igneous

Milky Quartz

Silicon Dioxide (SiO2)

mineral

Unakite

Epidotized Granite

metamorphic

Conglomerate

Clastic Conglomerate (Lithic-rich)

sedimentary

Quartz with Hematite Inclusions

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

mineral

Amygdaloidal Basalt with Epidote

Vesicular Basalt with secondary Epidote/Quartz mineral infill

igneous

Pink Quartzite

Quartzite (primarily SiO2)

metamorphic

Hag Stone

Calcareous sedimentary rock (often Chert, Flint, or Limestone)

sedimentary

Granite

Plutonic felsic rock (Quartz, Feldspar, Mica)

igneous

Chert (Jasper/Flint variant)

Silicon Dioxide (SiO2)

sedimentary

Amygdaloidal Basalt

Amygdaloidal Basalt (Mafic Volcanic Rock)

igneous

Quartzite

Quartzite (primarily SiO2)

metamorphic

Pink Granite

Granite (Felsic Plutonic Rock)

igneous

Quartzite River Cobble

Quartzite (SiO2)

metamorphic

Gneiss

Gneiss

metamorphic

Diorite

Diorite

igneous

Peridot

Olivine (Magnesium Iron Silicate - (Mg, Fe)2SiO4)

mineral

Basalt

Basalt (composition of plagioclase feldspar, pyroxene, and olivine)

igneous

Granite

Granite (Phaneritic igneous rock)

igneous

Granite

Granite (Felsic Intrusive Igneous Rock)

igneous

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite

Quartzite (primarily SiO2)

metamorphic

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

metamorphic

Sandstone (likely Quartzose Sandstone)

Arenite (SiO2 based)

sedimentary

Sodalite

Sodalite (Na8Al6Si6O24Cl2)

mineral

Dendritic Agate

Silicon Dioxide with Manganese/Iron oxide inclusions (SiO2)

Mineral

Petrified Wood

Silicified Wood (primarily SiO2)

sedimentary

Sardonyx Cameo

Silicon Dioxide (SiO2) - variety Cryptocrystalline Quartz

Mineral

Shell Cameo (Sardonyx Shell)

Cassis madagascariensis (Sardonyx shell)

mineral (biogenic silica/calcium carbonate substrate)

Pearl

Biogenic Calcium Carbonate (Aragonite/Calcite), CaCO3

mineral

Pearl

Calcium carbonate (CaCO3) in the form of Aragonite or Calcite

mineral

Pearl

Calcium carbonate (CaCO3) + organic conchiolin (Biogenic Mineral)

mineral

Pearl

Calcium Carbonate (Aragonite) - CaCO3

mineral

Pearl (as a biogenic mineral/gemstone)

Calcium Carbonate (mostly Aragonite), CaCO3

mineral

Pearl

Aragonite (CaCO3) with Conchiolin

mineral

Pearl (nacre)

Calcium Carbonate (mostly CaCO3 as Aragonite) and Conchiolin

Organic Mineraloid

Sandstone (with Lichen)

Arenite (composed primarily of SiO2)

sedimentary