Agate
SiO2 (Silicon Dioxide - Chalcedony)
Category
Browse metamorphic or sedimentary depending on local grade specimens identified by the Rock Identifier community.
Agate
SiO2 (Silicon Dioxide - Chalcedony)
Ferruginous Quartz
Silicon Dioxide (SiO2) with Hematite/Limonite impurities
White Quartz (Milky Quartz)
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Blue Opal in Matrix
Hydrated Silica (SiO2·nH2O)
Carnelian Agate
Chalcedony (Silicon Dioxide, SiO2) with Iron Oxide impurities
Optical Calcite (Iceland Spar)
Calcium Carbonate (CaCO3)
Glauconitic Sandstone
Glauconitic Quartz Arenite
Green Kyanite
Kyanite (Al2SiO5)
Magnetite with Quartz
Magnetite (Fe3O4)
Aragonite Star Cluster
Aragonite (Calcium Carbonate, CaCO3)
Sandstone (Ferruginous)
Arenite with Iron Oxide cement
Sunstone and Green Aventurine
Sunstone: (Ca,Na)[(Al,Si)2Si2O8] (Plagioclase Feldspar Group); Green Aventurine: SiO2 (Quartz)
Sapphire
Corundum (Al₂O₃) with trace elements causing color variations.
Limonite (Ironstone)
Limonite (mixture of hydrated iron(III) oxide-hydroxides)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Sandstone
Quartz Sandstone (predominantly)
Nephrite Jade
Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Red Sandstone
Arenite (with Iron Oxide / Hematite cementation)
Puddingstone
Conglomerate
Cardstock (Paper)
Cellulose (C6H10O5)n
Quartz (Rock Crystal)
Silicon Dioxide (SiO2)
Milky Quartz
Quartz (Silicon Dioxide, SiO2)
Blue Apatite
Fluorapatite (Ca5(PO4)3F)
Milky Quartz/White Quartz
Silicon Dioxide (SiO2)
Milky Quartz
Silicon Dioxide (SiO2)
Pyrite
Iron Disulfide (FeS2)
Green Quartz (Prasiolite/Adventurine)
Silicon Dioxide with inclusions (SiO2)
Specular Hematite
Hematite (Fe2O3)
Citrine
SiO2 (Silicon Dioxide)
Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
Pyrite
Iron Sulfide (FeS2)
Sandstone (likely Quartzose Sandstone)
Arenite (primarily SiO2)
Specular Hematite (on Schist/Matrix)
Hematite (Alpha-Fe2O3)
Milky Quartz in Matrix
Silicon Dioxide (SiO2)
Pyrite
Iron Sulfide (FeS2)
Aquamarine
Beryl (Be3Al2Si6O18)
Aventurine (Green Aventurine)
Quartz with Fuchsite Inclusions (SiO2)
Smoky Quartz
SiO2 (Silicon Dioxide)
Optical Calcite
Calcium Carbonate (CaCO3)
Red Jasper
Red Jasper (SiO2)