Cullet (Slag Glass)
Amorphous Silica (SiO2) with various metal oxide colorants
mineraloid / anthropogenic
Category
Organic Mineraloid
Browse organic mineraloid specimens identified by the Rock Identifier community.
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Opalite
Synthetic Glass, SiO2 base with metallic inclusions
mineraloid (synthetic)
Libyan Desert Glass
Tektite (high-silica impact glass), SiO2 + tracing minerals
mineraloid / impactite
Slag (Industrial Glass Slag)
Amorphous Silica / Ferro-silicate Slag
mineraloid / anthropogenic
Mother of Pearl (Nacre)
Aragonite (CaCO3) with Organic Matrix
mineral
Seashell Fragment
Calcium carbonate (CaCO3) - primarily Aragonite or Calcite
fossil
Black Limestone
Bituminous Limestone (Calcium Carbonate - CaCO3)
sedimentary
Fossilized Bone
Vertebrate fossil (mineralized bone)
fossil
Pyritic Shale
Carbonaceous Shale with Iron Pyrite (FeS2)
sedimentary
Amber
Succinite (Approximate formula: C10H16O)
mineral
Fossilized Wood / Petrified Wood
Petrified Wood (Silicified Flora)
fossil
Slag (Industrial Glass)
Artificial Vitreous Silicate
mineraloid (anthropogenic)
Sea Glass
Amorphous Silica (SiO2) with various additives
Mineraloid (Anthropogenic)
Opalite
Man-made Glass (SiO2 + additives)
mineraloid (synthetic)
Slag
Ferrous slag (by-product of iron smelting)
Mineraloid / Anthropogenic
Moldavite
Silica glass with small amounts of aluminum, iron, and other elements
Mineraloid / Tektite
Polished black stone egg, probably black obsidian
Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements
gemstone
Chert (Green Fossilized Algae or Jasper)
Silicon Dioxide (SiO2)
sedimentary
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3
gemstone
Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Organic (Non-geological)
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Fossilized Bone
Permineralized Vertebrate Bone
fossil
Chert (Jasper/Chalcedony mix)
Microcrystalline Quartz (SiO2)
sedimentary
Freshwater Pearl
Aragonite / Biogenic Calcium Carbonate (CaCO3)
mineral
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
sedimentary
Obsidian
Obsidian (volcanic glass)
Igneous
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
mineral
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
mineral
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin
gemstone
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Fossilized Shell Fragment / Mother of Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral
fossil
Pearl
Calcium Carbonate (CaCO3) with Conchiolin
mineral
Limestone or Sandstone Cobble
Sedimentary rock (Calcium carbonate or Quartz based)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Black Chert
Carbonaceous Chert (Silicon dioxide, SiO2)
sedimentary
Pearl
Calcium carbonate (CaCO3) as Aragonite or Calcite
mineral
Fossiliferous Sandstone
Sedimentary rock containing invertebrate fossils
fossil
Chert (Green and Black Jasper variant)
Cryptocrystalline Quartz (SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Amber
Succinite (C10H16O)
mineral
Amber
Succinite (Organic Gemstone)
mineral
Amber / Copal
Organic resin, C10H16O
mineral