Black Opal
Hydrated Silica (SiO2·nH2O)
Category
Browse sedimentary (or mineraloid) specimens identified by the Rock Identifier community.
Black Opal
Hydrated Silica (SiO2·nH2O)
Amber / Copal
Succinite (fossilized tree resin)
Limonite (Iron Ore)
Limonite (Hydrous ferric oxides), generic formula FeO(OH)·nH2O
White Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Baltic Amber
Succinite (Polmerized conifer resin)
Blue Opal Inlay (Simulated/Lab-created)
Hydrated Amorphous Silica (SiO2·nH2O) with polymer resin
Amber
Succinite (approximate formula C10H16O)
Amber
Succinite (fossilized resin); C10H16O
Amber
Succinite (with approximate formula C10H16O)
Amber
Succinite (a fossilized organic resin containing succinic acid)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Opal (Precious Opal)
Hydrated Silica (SiO2·nH2O)
Amber
Succinite
Amber / Copal
Fossilized Tree Resin (Succinate)
Common Opal (Green Opal / Pistachio Opal)
Hydrated silica (SiO2·nH2O)
Limonite (Ironstone Concretion)
Limonite (Hydrated iron(III) oxide-hydroxide, mixtures of FeO(OH)·nH2O)
Limonite (with Pyrite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Amber (Black)
Amber (succinite, retinite, etc., specifically, heavily included/dark varieties)
Limonite Concretion
Hydrated iron(III) oxide-hydroxide (FeO(OH)·nH2O)
Fulgurite
Fulgurite (Lechatelierite-rich fused silica)
Limonite (Iron Ore)
Hydrous ferric oxides (FeO(OH)·nH2O)
Common Opal with Host Rock
Opal (Hydrated silica, SiO2·nH2O)
Precious Opal
Hydrated Silica (SiO2·nH2O)
Limonite (Iron Ore/Sandstone mixture)
Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix
Yellow Ocher (Limonite)
Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O
Limonite (Yellow Ochre)
Limonite (an amorphous mixture of hydrated iron oxides, primarily FeO(OH)·nH2O)
Opal
Hydrated Amorphous Silica (SiO2·nH2O)
Fulgurite
Fulgurite (Lechatelierite)
Black Obsidian
Volcanic Glass (SiO2 + impurities)
Limonite and Goethite (Ironstone)
Hydrous Iron Oxide Mixture (FeO(OH)·nH2O)
Obsidian
Volcanic glass
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
White Opal (Common)
Hydrated Silica (SiO2·nH2O)
Gold Sheen Obsidian
Volcanic Glass (SiO2 + Fe3O4 / Gas Inclusions)
Pearl
Calcium Carbonate (Aragonite) with Conchiolin; formula: CaCO3
Pearl
Organic Mineraloid (CaCO3 + Conchiolin)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Obsidian
Obsidian (Amorphous volcanic glass, predominantly SiO2)
Obsidian
Volcanic glass (SiO2 - Silicon Dioxide with impurities)
Limonite (Iron Ore)
Hydrated Iron(III) Oxide-Hydroxide (FeO(OH)·nH2O)
Obsidian
Volcanic Glass (SiO2 rich)
Anthracite Coal
Anthracite (Carbon-rich mineraloid)