Fossiliferous Rock (Invertebrate Fossil in Matrix)
Fossiliferous limestone or shaly matrix containing skeletal fossil remains
fossil
Category
Amorphous Solid
Browse amorphous solid specimens identified by the Rock Identifier community.
Learn about Amorphous Solid in the encyclopedia
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Pumice (Vesicular Lava)
Pumice
igneous
Slag
Metallurgical Slag
igneous
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Limonite and Goethite encrusted Quartz (Iron-stained Gossan)
FeO(OH)·nH2O (Limonite) / FeO(OH) (Goethite) on SiO2 (Quartz)
mineral
Obsidian / Volcanic Glass
Obsidian (principally SiO2, usually 70% or more)
igneous
Coquina
Bioclastic Limestone (composed primarily of CaCO3)
sedimentary
Chrysocolla
Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Obsidian
Volcanic glass
igneous
Amber
Fossilized Tree Resin (Succinite)
mineraloid
Sandstone with Vitrinite/Coal inclusions
Arenite with Carbonaceous inclusions
sedimentary
Ironstone Nodule (Ironstone Concretion)
Siderite-rich Mudstone (FeCO3) or Limonite (FeO(OH)·nH2O)
sedimentary
Polished black stone pendant, likely obsidian
Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), if obsidian
igneous
Septarian Nodule
Septarian Concretion (Calcite, Aragonite, and Limestone)
sedimentary
Chrysocolla in Matrix
Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Vesicular Basalt with Zeolite
Mafic volcanic rock with Hydrated Aluminosilicate minerals (Zeolite group)
igneous
Amber
Amber (Fossilized Tree Resin)
Mineral
Pink Anthracite Coal (dyed)
Anthracite Coal (Artificially Colored)
Sedimentary Rock (Altered)
Opalite (a synthetic glass, often confused with Opal)
Silicon dioxide glass (SiO2nH2O, for natural opal)
Synthetic (glass)
Obsidian (likely Golden Sheen Obsidian or Rainbow Obsidian, given the subtle sheen visible on some beads)
Obsidian (volcanic glass, predominantly SiO2 with various impurities)
Igneous
Smoky Quartz
Quartz (SiO₂)
Mineral
Amber with dark mineral/organic inclusions
Fossilized plant resin (amber; chiefly polymerized diterpenoid resin)
gemstone
Pumice
Pumice (Volcanic glass / Felsic extrusive rock)
igneous
Green Opal / Common Opal
Hydrated Silicon Dioxide (SiO2·nH2O)
mineral
Anthracite Coal
Anthracite (a variety of coal, predominantly carbon)
Sedimentary Rock (Metamorphosed)
Pumice
Pumice (Vesicular Felsic to Intermediate Volcanic Rock)
igneous
Coral (Precious Coral)
Corallium rubrum (Red Coral), Paracorallium japonicum (Momo Coral), Pleurocorallium elatius (Sardinian Coral), various other species within the Corallidae family. Chemically, it's primarily Calcium Carbonate (CaCO 3 ).
Mineral, Organic Gemstone
Opal
Hydrous silicon dioxide (SiO2·nH2O)
mineral
Limonite (Iron Ore)
Limonite (an FeO(OH)·nH2O mineraloid, not a true mineral due to variable composition)
Mineral
Coal (most likely Bituminous or Anthracite)
Coal (primarily composed of carbon with varying amounts of other elements)
Sedimentary rock
Polished black stone, likely black obsidian
Obsidian (volcanic glass), primarily silica-rich rhyolitic composition
igneous
Chrysocolla
Hydrated copper phyllosilicate, (Cu,Al)2H2Si2O5(OH)4·nH2O
mineral
Obsidian
Volcanic Glass
igneous
Amber (Copal)
Organic gemstone, fossilized tree resin (often immature amber or copal)
Mineral
Obsidian
Obsidian (volcanic glass)
igneous
Petrified Wood
Silicified Wood / Fossilized Wood (SiO2)
sedimentary
Bauxite
Hydrated aluminium oxides mixture (primarily gibbsite, boehmite, and diaspore)
sedimentary
Septarian Nodule
Septarian Concretion (Calcium Carbonate/Aragonite/Calcite/Siderite)
sedimentary
Ironstone (likely Ferruginous Siltstone/Sandstone)
Ferruginous sedimentary rock (FeOx-rich clastic)
sedimentary
Laterite (iron-rich nodule, possibly Bauxite as a subtype)
Laterite (composed of various minerals including goethite, hematite, gibbsite, etc.)
Sedimentary
Polished black gemstone, likely black obsidian
Obsidian (volcanic glass), chiefly silica-rich amorphous SiO₂
igneous
Orange fire opal jewelry
Precious opal, hydrated amorphous silica (SiO₂·nH₂O)
gemstone