Mineral On Igneous Rock

Quartz Crystal (specifically a Double-Terminated variety)

Silicon Dioxide (SiO2) - Low Quartz

Agate

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sandstone (likely with Quartz Veining)

Arenite (primarily SiO2)

Sandstone (Picture Sandstone)

Sandstone (primarily Quartz with Iron Oxide impurities)

Red Sandstone (Old Red Sandstone)

Ferruginous Sandstone (SiO2 + Fe2O3)

Labradorite

Labradorite (a calcium-enriched sodic plagioclase feldspar mineral - (Ca, Na)(Al, Si)4O8)

Pyrite on Quartz matrix

Iron Disulfide (FeS2) on Silicon Dioxide (SiO2)

Quartz crystal with Pyrite inclusions

Silicon Dioxide (SiO2) with Iron Sulfide (FeS2)

Pumice

Vesicular Rhyolite or Dacite

Obsidian

Obsidian (Volcanic Glass), primarily SiO2 (70% or more silicon dioxide)

Granite

Granite (Mainly Quartz SiO2, K-Feldspar KAlSi3O8, and Plagioclase)

Obsidian

Volcanic Glass (SiO2 - Silicon Dioxide with impurities)

Granite

Phaneritic Plutonic Felsic Rock (SiO2 > 63%)

Spinifex Textured Komatiite

Komatiite (Mg-rich ultramafic volcanic rock)

Scoria

Vesicular Basalt / Scoria (Mafic silicate rock)

Granite

Phaneritic Plutonic Felsic Rock (SiO2 > 69%)

Porphyritic Basalt

Porphyritic Fine-grained Mafic Volcanic Rock

Scoria

Vesicular Basalt / Scoria (Mafic volcanic rock)

Porphyritic Basalt (Peanut Obsidian/Star Galaxy-style)

Porphyritic Basalt (Silica-rich Volcanic Rock)

Bornite

Bornite (Cu5FeS4)

Kaolinite (Chalky Clay)

Kaolinite (Al2Si2O5(OH)4)

Bauxite

Bauxite (Al(OH)3, AlO(OH))

River Rock

Sedimentary Rock (various compositions)

River Pebble (Likely Chert or Fine-Grained Sandstone/Quartzite)

Siliciclastic clast (likely Chert or Quartzarenite/Quartzite pebble)

Granite

Phaneritic plutonic rock (Quartz, Feldspar, Mica)

Granite

Granite (Felsic Plutonic Rock / SiO2 + Al2O3)

Basalt

Mafic Volcanic Rock (Primarily Plagioclase and Pyroxene)

River Pebble (Gabbro or Dark Sandstone variety)

Mafic Intrusive Rock (Plagioclase Feldspar and Pyroxene)

Shale

Fissile mudrock (composed primarily of clay minerals and quartz)

Quartz

Silicon dioxide (SiO₂)

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Sandstone (Ferruginous)

Arenite with Iron Oxides

Sandstone (Ferruginous)

Arenite with Iron Oxide cement (SiO2 + Fe2O3)

Jasper and Basalt Mix (Dark Chert/Basalt River Pebble)

Silicon Dioxide (SiO2) or Mafic extrusive igneous rock

Sandstone

Arenite (Siliclastic sedimentary rock), SiO2 + various minerals

Banded Agate

Cryptocrystalline variety of Quartz (SiO2)

Agate

Silicon Dioxide (SiO2)

Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Druzy Quartz Geode (Vug)

Silicon Dioxide (SiO2)

Quartz Pebble (Water-worn Quartzite)

Silicon Dioxide (SiO2)

Bauxite

Bauxite (mixture of Hydrous Aluminum Oxides)