Man Made Rock (Technosol)

Basalt with Olivine Phenocrysts

Porphyritic Basalt (Mineral formula of Olivine: (Mg,Fe)2SiO4)

Milky Quartz with Matrix

Quartz (Silicon Dioxide, SiO2)

Gneiss

Gneiss (a rock type, not a specific mineral with a formula)

Sandstone with Quartz Veining

Arenite with hydrothermal quartz (SiO2)

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (primarily SiO2)

Biotite Mica

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

Blue Apatite

Apatite group (Ca5(PO4)3(F,Cl,OH))

Blue Sapphire (Tumbled/Polished)

Corundum (Al2O3)

Sodalite

Sodalite [Na8(Al6Si6O24)Cl2]

Granite River Pebble

Phaneritic Felsic Igneous Rock (Granite)

Porphyritic Andesite

Andesite (Intermediate Extrusive Volcanic Rock)

Basalt (River Pebble)

Basalt (Aphanitic Mafic Volcanic Rock)

Milky Quartz

Quartz / Silicon Dioxide (SiO2)

Chalcedony (Grey/White Agate)

Silicon Dioxide (SiO₂)

Smoky Quartz

Silicon Dioxide (SiO2)

Opal

Hydrated Amorphous Silica (SiO2·nH2O)

Labradorite

(Ca, Na)(Al, Si)4O8

Yellow Quartz (Citrine or Yellow Jasper)

Silicon Dioxide (SiO2)

Geode (Chert or Quartz Nodule)

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Sandstone

Arenite (SiO2 based with various cements)

Granite

Phaneritic Plutonic Rock (primarily Quartz, Feldspar, and Mica/Amphibole)

Carnelian

Carnelian (Silicon Dioxide, SiO2)

Moonstone (Feldspar)

Orthoclase feldspar, (K,Na)AlSi3O8

Labradorite

Labradorite ((Ca, Na)(Al, Si)4O8)

Milky Quartz

Silicon Dioxide (SiO2)

Muscovite Mica

Muscovite / KAl2(AlSi3O10)(OH)2

Amethyst (Purple Quartz)

Silicon Dioxide (SiO2) with iron impurities

Quartz on Host Rock

Silicon Dioxide (SiO2)

Pink Feldspar

Orthoclase Feldspar (KAlSi3O8)

Orthoclase Feldspar

Orthoclase (KAlSi3O8)

Red Sandstone (Iron-rich)

Ferruginous Sandstone (variable formula, primarily SiO2 + Fe2O3)

Chert (concretionary/nodular variant)

Microcrystalline Quartz (SiO2) with possible fossil or mineral inclusions

Boulder Opal

Precious Opal in Ironstone (Amorphous Hydrated Silica, SiO2·nH2O)

Basalt

Basalt (Extrusive Mafic Igneous Rock)

Basalt

Mafic volcanic rock (primarily plagioclase feldspar and pyroxene)

Granite

Granite (a felsic intrusive igneous rock)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 cement)

Granite

Phaneritic Felsic Igneous Rock (Granite)

Gneiss

Gneiss (High-grade regional metamorphic rock)

Porphyritic Basalt

Porphyritic Basalt (Mafic extrusive rock)