Basalt

Basalt with Peridotite Inclusion

Mafic Volcanic Rock (Extrusive Igneous) with Ultramafic Xenolith

Olivine (Peridot)

Magnesium Iron Silicate (Mg, Fe)2SiO4

Olivine (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Quartz Druse (on Chalcedony/Agate base)

Silicon Dioxide (SiO2)

Amethyst

Silicon dioxide (SiO2) with iron impurities

Banded Agate

Cryptocrystalline Quartz (SiO2)

Olivine (Peridotite)

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

Peridot

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

Granodiorite with Quartz Veining

Granodiorite (containing Plagioclase Feldspar, Quartz, and Biotite/Hornblende) with Quartz (SiO2) veins

Porphyritic Basalt (likely Chinese Writing Stone)

Porphyritic Basalt / Plagioclase Feldspar in Basal Matrix

Granite

Phaneritic Felsic Igneous Rock

Amethyst (Quartz)

Silicon Dioxide (SiO2)

Greenschist / Chloritaform Schist

Chlorite Schist (Group of Silicate Minerals)

Sunstone

Oligoclase or Andesine (Plagioclase Feldspar) - (Ca, Na)((Al, Si)2Si2O8)

Greenschist

Chlorite schist

River Rock (Basalt/Greywacke pebbles)

Fluvial gravel primarily composed of Mafic Volcanic Rock (Basalt) or Lithic Sandstone (Greywacke)

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide impurities

Banded Agate (Carnelian type)

Silicon Dioxide (SiO2) - Cryptocrystalline Chalcedony

Banded Agate (specifically Chalcedony nodule)

Agate (Silicon Dioxide, SiO2)

Carnelian

Carnelian (a variety of Chalcedony, SiO2)

Parti Sapphire

Corundum (Al2O3)

Agate

Banded Chalcedony (SiO2)

Gabbro

Gabbro (mafic intrusive igneous rock)

Greenstone or Chlorite Schist

Greenschist / Chlorite schist

Bauxite

Bauxite (Al2O3·nH2O)

Blue Sapphire

Corundum (Al2O3)

Carnelian (Chalcedony)

Silicon Dioxide (SiO2) with trace Iron Oxide

Blue Sapphire

Corundum (Al2O3 with trace Titanium/Iron)

Amphibolite with Hornblende

Amphibole-rich Metamorphic Rock (Ca2(Mg,Fe)5Si8O22(OH)2)

Greenstone (Epidote/Chlorite Schist)

Metabasalt (composed primarily of Epidote Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH) and Chlorite (Mg,Fe)3(Si,Al)4O10(OH)2·(Mg,Fe)3(OH)6)

Basalt with Quartz/Feldspar Inclusions

Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining

Basalt (River Pebble)

Basalt (dominated by Plagioclase Feldspar and Pyroxene)

Olivine (Peridot when gem-quality)

Magnesium Iron Silicate, (Mg,Fe)2SiO4

Peridot

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

Blue Chalcedony

Chalcedony (SiO2)

Aquamarine with Ruby Accent

Beryllium Aluminum Silicate (Be3Al2Si6O18) with Aluminum Oxide (Al2O3)

Amethyst

Quartz (Silicon Dioxide with iron impurities), SiO2

Quartz Veined Basalt Pebble

Amygdaloidal Basalt with Quartz (SiO2) veining

Chinese Writing Stone

Porphyritic Basalt (or Andesite) with Feldspar inclusions

Porphyritic Basalt (Chinese Writing Stone)

Porphyritic Basalt with Andalusite or Feldspar laths

Scoria (Lava Rock)

Extrusive Igneous Scoria (Vesicular Basalt)

Basalt River Stone

Basalt (Aphanitic Mafic Igneous Rock)