Anthropogenic Specimen (Man Made)

Basalt River Pebble

Basalt (fine-grained mafic igneous rock)

Sandstone

Arenite (primarily SiO2)

Gabbro (Water-Worn Cobble)

Gabbro

Granite

Granite (Phaneritic igneous rock)

Milky Quartz

Silicon Dioxide (SiO2)

Red Jasper with Quartz

Silicon Dioxide (SiO2) with Hematite inclusions

Chert (and Limestone)

Silicon Dioxide (SiO2)

Banded Calcite (often sold as Onyx or Mexican Onyx)

Calcite (Calcium Carbonate, CaCO3)

Basalt (Water-worn Pebble)

Basalt (Aphanitic Mafic Igneous Rock)

Sandstone (Quartz-rich)

Clastic sedimentary rock (SiO2 primary)

Banded Agate (Botswana Agate)

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite (with Goethite/Limonite cement)

Chert (Arrowhead Fragment)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Porphyry (likely Porphyritic Andesite or Basalt)

Porphyritic Igneous Rock

Quartz Pebble (Hag Stone / Adder Stone)

Silicon Dioxide (SiO2)

Porous Quartzite

Metamorphosed Quartz-rich Sandstone (SiO2)

Agate

Silicon Dioxide (SiO2) - variety Chalcedony

Calcite

Calcium Carbonate (CaCO3)

Satin Spar (often marketed as Selenite)

Fibrous Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

Chalcedony (Botryoidal Agate vein)

Chalcedony (Microcrystalline Quartz) - SiO2

Jasper with Quartz Vein

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Basalt with Jasper Veining

Basaltic Rock with Cryptocrystalline Quartz (SiO2)

Banded Calcite (often sold as 'Mexican Onyx')

Calcite (Calcium Carbonate, CaCO3)

Jasper

Silicon dioxide (SiO2)

Granitic Pegmatite

Granite Pegmatite (coarse-grained intrusive igneous rock)

Sandstone (Quartzose Pebble)

Clastic sedimentary rock (primarily SiO2)

Honey Calcite

Calcium Carbonate (CaCO3)

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with Fe2O3)

Pink Marble or Rose Quartz (Likely Pink Marble based on carving texture)

Recrystallized Calcite (CaCO3)

Banded Agate (Yellow Agate)

Silicon Dioxide (SiO2)

Milk Quartz (with Iron staining)

Silicon Dioxide (SiO2)

Jasper with Agate Inclusions

Jasper (Silicon Dioxide, SiO2) with Chalcedony/Agate

Quartzite Breccia

Brecciated Quartzite (SiO2)

Sandstone (Weathered Coastal Boulder)

Arenite (composed primarily of SiO2)

Chert (often called Flint when in chalk or limestone)

Silicon Dioxide (SiO₂)

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Biotite Gneiss

Gneiss (complex mixture including Biotite K(Mg,Fe)3AlSi3O10(F,OH)2 and Quartz/Feldspar)

Quartzite River Rock (with Quartz Vein)

Quartzite (SiO2)

Blue Dyed Agate

Chalcedony (SiO2) with artificial pigment

Yellow Calcite (Banded Calcite)

Calcium Carbonate (CaCO3)

Chalcedony (Agate/Chert)

Microcrystalline Quartz (SiO2)

Quartz with Mica inclusions (Gold-colored Mica)

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (Phlogopite/Muscovite) inclusions