Seashell Fragment
Calcium carbonate (CaCO3) - primarily Aragonite or Calcite
fossil
Category
Organic Mineraloid
Browse organic mineraloid specimens identified by the Rock Identifier community.
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Horse Chestnut (Buckeye seed)
Aesculus hippocastanum seed
Organic (Non-geological)
Amber
Succinite (Approximate formula: C10H16O)
mineral
Ambergris
Physeter macrocephalus excreta (Ambergris)
mineraloid / organic geological find
Ambergris
Ambrein (C30H52O)
mineraloid / organic geological substance
Natural Pearl
Calcium carbonate (primarily Aragonite and Conchiolin), CaCO3
mineral
Chert (Jasper/Chalcedony mix)
Microcrystalline Quartz (SiO2)
sedimentary
Fossilized Bone
Permineralized Vertebrate Bone
fossil
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Amber
Succinite (Organic Gemstone)
mineral
Amber / Copal
Organic resin, C10H16O
mineral
Pearl
Calcium Carbonate (Aragonite/Calcite) with Conchiolin, CaCO3
gemstone
Pearl
Calcium carbonate (CaCO3) in the form of aragonite
gemstone
Freshwater Pearl
Aragonite / Biogenic Calcium Carbonate (CaCO3)
mineral
Man-made Glass (Tumbled/Shaped)
Amorphous Silicon Dioxide (SiO2) with metal oxide colorants
Mineraloid (synthetic)
Opalite
Synthetic Fluorescent Glass (SiO2 + impurities)
mineraloid (synthetic)
Synthetic Convention Badge (Plastic/PVC)
Polyvinyl Chloride (PVC) / Polycarbonate
mineraloid (synthetic)
Jade (likely Jadeite or Nephrite)
Jadeite (NaAlSi2O6) or Nephrite (Ca2(Mg,Fe)5Si8O22(OH)2)
Mineral/Mineraloid
Jade
Jadeite or Nephrite
Mineral/Mineraloid
Yellow Jasper
Jasper (Silicon Dioxide, SiO2)
sedimentary (or mineraloid)
Opalite (Synthetic Moonstone/Opal)
Synthetic Silica Glass
mineraloid (synthetic)
Opalite
Synthetic Opalised Glass
mineraloid (synthetic)
Cullet (Slag Glass)
Amorphous Silica (SiO2) with various metal oxide colorants
mineraloid / anthropogenic
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
Black Limestone with Calcite Veining
Bituminous Limestone (CaCO3 with Organic Carbon inclusions)
sedimentary
Amber cabochon pendant
Amber (fossilized tree resin; chiefly polymerized terpenoids)
gemstone
Red Coral
Corallium rubrum
gemstone
Manganese Dendrite on Siltstone
Manganese Oxide (pyrolusite or psilomelane) Dendrites
mineral/sedimentary
Kidney Stone
Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)
mineral
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
Black Chert
Carbonaceous Chert (Silicon dioxide, SiO2)
sedimentary
Petrified Wood
Silicified Wood (SiO2)
fossil
Fossilized Shell Fragment
Invertebrate marine fossil, likely calcium carbonate replacement
fossil
Shale or Slate
Shale (Sedimentary) or Slate (Metamorphic)
sedimentary or metamorphic
Fossilized Shell Fragment / Mother of Pearl
Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral
fossil