Sandstone

Arenite (primarily Quartz, SiO2)

sedimentary

Quartz with Mica inclusions (likely Iron-stained)

Silicon Dioxide (SiO2) with Phyllosilicates

mineral

Granitic Gneiss

Gneiss (High-grade regional metamorphic rock)

metamorphic

Sandstone (Gneissic or Banded)

Clastic Sedimentary Rock (composed predominantly of SiO2)

sedimentary

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions of Iron Oxide)

Metamorphic

Agate Geode

Silicon Dioxide (SiO2) - Chalcedony / Quartz Variety

Mineral

Satin Spar (Selenite)

Gypsum (Calcium Sulfate Dihydrate) - CaSO4·2H2O

mineral

Yellow Aventurine

Quartz (Silicon Dioxide - SiO2) with inclusions of Mica

Mineral

Sodalite

Na8(Al6Si6O24)Cl2

mineral

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of titanium, iron, or manganese

mineral

Rose Quartz

Silicon dioxide with traces of titanium, iron, or manganese (SiO2)

mineral

Red Jasper

Jasper (Silicon Dioxide with Hematite inclusions), SiO2

sedimentary

Green Aventurine

Silicon Dioxide (SiO2 with Fuchsite inclusions)

metamorphic

Green Aventurine

Silicon dioxide with Fuscite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

mineral

Amethyst (Tumbled)

Amethyst (Silicon Dioxide with Iron impurities) - SiO2

mineral

Jasper

Jasper (Silicon Dioxide, SiO2)

sedimentary

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

mineral

Carnelian Agate

Carnelian (Silicon Dioxide - SiO2)

mineral

Banded Agate (specifically Sardonyx or Carnelian Agate)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

mineral

Aragonite Star Cluster

Aragonite (Sputnik habit) - CaesarCO3

mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

mineral

Picture Jasper

Silicon Dioxide (SiO2) with iron oxide and clay inclusions

sedimentary

Clear Quartz

Silicon Dioxide (SiO2)

mineral

Blue Lace Agate

Silicon Dioxide (SiO2)

mineral

Rose Quartz

Silicon Dioxide (SiO2) with trace amounts of Titanium, Iron, or Manganese

mineral

Pink Opal

Hydrated Silica (SiO2·nH2O)

mineral

Banded Agate (specifically Carnelian Agate)

Silicon dioxide (SiO2) - Chalcedony variety

mineral

Jasper

Jasper (Silicate mineral, SiO2)

sedimentary

Leopard Skin Jasper

Jasper (Silicon Dioxide with impurities), SiO2

sedimentary

Moss Agate

Silicon Dioxide (SiO2) with mineral inclusions

Mineral

Amethyst (Quartz variety)

Amethyst [Silicon Dioxide (SiO2)]

mineral

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

sedimentary

Agate

Banded Chalcedony (SiO2)

mineral

Blue Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

metamorphic

Malachite

Malachite - Cu2CO3(OH)2

mineral

Dyed Pink Agate

Silicon Dioxide (SiO2) - variety Chalcedony

mineral

Pyrite

Iron Sulfide (FeS2)

mineral

Dendritic Moss Agate

Chalcedony (Silicon Dioxide, SiO2) with inclusions

mineral

Kunzite (variety of Spodumene)

Lithium Aluminum Silicate (LiAlSi2O6)

mineral

Red Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with Fe2O3 inclusions)

metamorphic

Tiger's Eye

SiO2 (Silicon Dioxide with inclusions of Goethite/Limonite)

Metamorphic

Agate (Sliced Nodule)

Silicon Dioxide (SiO2) - Chalcedony variety

mineral