Not A Rock (Animated Character)

Arfvedsonite (often mistakenly sold as Astrophyllite)

Arfvedsonite [Na3(Fe2+)4Fe3+Si8O22(OH)2]

Limonite Concretion

Limonite (Hydrated iron(III) oxide-hydroxides, FeO(OH)·nH2O)

Iron-rich weathered rock, possibly limonite/goethite-bearing ore

Limonite (hydrated iron oxides; chiefly goethite, FeO(OH), with hematite and other oxides possible)

Pink Opal

Amorphous Hydrous Silica (SiO2·nH2O)

Moss Agate

Chalcedony (SiO2) with inclusions of manganese or iron oxides

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Ferruginous Sandstone

Sandstone (arenite) with Limonite/Goethite cement

Hematite

Hematite (Fe2O3)

Clear Quartz (Druzy/Crystal Cluster)

Silicon Dioxide (SiO2)

Blue Agate

Chalcedony (SiO2)

Limonite Concretion (Ironstone)

Limonite / Goethite (FeO(OH)·nH2O)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Rhodonite

Manganese Silicate (Mn,Fe,Mg,Ca)SiO3

Iron Ore / Hematite Rock

Iron oxide (primarily Hematite, Fe2O3)

Limonite Concretion

Limonite (FeO(OH)·nH2O)

Stromatolite

Biogenic sedimentary rock

Amethyst

Silicon Dioxide (SiO2)

Barite

Barium Sulfate (BaSO4)

Greenschist

Greenschist

Black Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Serpentine

Serpentine (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

Feldspar (with Quartz / Iron Staining)

Potassium Feldspar / Plagioclase (KAlSi3O8 - NaAlSi3O8 to CaAl2Si2O8)

Green Moss Agate (Tumbled)

Silicon Dioxide (SiO2) with mineral inclusions

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Clear Quartz

Silicon Dioxide (SiO2)

Moss Agate and Hematite

Silica (SiO2) with fibrous inclusions of Manganese or Iron; Hematite (Fe2O3)

Coral Fossil (Scleractinia)

Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)

Green Aventurine

Quartz variant (SiO2) with Fuchsite inclusions

Moss Agate

Silicon Dioxide (SiO2) with inclusions

Biotite-bearing granite or granitic gneiss

Quartz–feldspar–biotite aggregate; likely granite, possibly weathered gneiss

Biotite-bearing metamorphic rock, possibly schist or gneiss

Mica schist/gneiss; chiefly quartz (SiO₂), feldspar, and biotite mica

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Epidosite

Epidosite (predominantly Epidote {Ca2Al2Fe3+Si3O12(OH)} and Quartz {SiO2})

Amethyst

Silicon dioxide (SiO2)

Obsidian

Volcanic Glass

Amazonite

Microcline (KAlSi3O8) with trace lead (Pb)

Carnelian Agate

Silicon Dioxide (SiO2) with iron oxide inclusions

Dalmatian jasper

Dalmatian stone, typically a leucocratic alkali-feldspar-rich porphyritic igneous rock with black arfvedsonite or aegirine inclusions

Carnelian Agate

Silicon Dioxide (SiO2)

Sunstone (Orthoclase Feldspar variant)

Orthoclase (KAlSi3O8) with inclusions

Marble

Recrystallized Calcite (CaCO3) or Dolomite (CaMg(CO3)2)

Muscovite mica

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂