Pearls
Pearl: biomineralized aragonite (CaCO₃) and conchiolin
gemstone
Category
Organic (Non Rock)
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Note on Image Identification: Textile
N/A (Anthropogenic material)
not a rock
Siltstone
Siltstone (composed of microscopic quartz and clay minerals)
sedimentary
Quartz Pebble
Silicon Dioxide (SiO2)
mineral
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Blue Opal in Matrix
Hydrated Silica (SiO2·nH2O)
mineral
Moss-covered Limestone with Quartz/Calcite Pocket
Calcium Carbonate (CaCO3) rock with biological moss coating
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Amber
Succinite (a specific common type) or Fossilized Tree Resin (C10H16O)
Mineraloid
Quartzite with inclusions
Metamorphic Rock (Mainly SiO2)
metamorphic
Fossilized Bone
Petrified Bone / Biogenic Sedimentary
fossil
Basalt
Mafic Igneous Rock
igneous
Snowflake Obsidian
Volcanic glass (SiO2) with Cristobalite (SiO2) inclusions
igneous
Black Obsidian
Volcanic glass
igneous
Note: This is a Man-Made Object (Costume/Prop Patch)
Synthetic fiber and pigments (Cellulose/Plastic-based composite)
Non-geological
Fossil Crab
Decapoda (likely Avitelmessus or Raninidae family)
sedimentary
Shale (with Iron Staining)
Argillaceous mudstone / Shale
sedimentary
Opalite
Synthetic Opalised Glass
Mineral (Synthetic / Man-made)
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Siltstone Pebble
Siltstone (fine-grained siliciclastic sedimentary rock)
sedimentary
Pink granite or pink feldspathic rock
Granite, chiefly quartz, potassium feldspar, and plagioclase; exact identification is uncertain from the image
igneous
Coal (Anthracite or Bituminous)
Carbonaceous sedimentary rock (Carbon)
sedimentary
Snowflake Obsidian
Volcanic Glass (spherulitic obsidian)
igneous
Amber
Succinite (fossilized tree resin, C10H16O)
fossil
Moldavite
Moldavite (Siliceous vitreous substance)
tektite (natural glass)
Green Sea Glass
Amorphous Silica (man-made glass), SiO2 + additive metal oxides
mineraloid / anthropogenic (man-made origin)
Eclogite
Eclogite (Omphacite-Garnet Rock)
metamorphic
Fossilized Coral
Cnidaria (Anthozoa), often replaced by Calcium Carbonate (CaCO3) or Silica (SiO2)
sedimentary
Chert (Green and Black Jasper variant)
Cryptocrystalline Quartz (SiO2)
sedimentary
River Pebble (Siltstone/Mudstone)
Clastic sedimentary rock
sedimentary
Quartzite
Quartzite (chiefly SiO2)
metamorphic
Quartzite
Quartzite (predominantly SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Basalt (River Pebble)
Basalt
igneous
Chert Nodules or Concretion
Cryptocrystalline Quartz (SiO2)
sedimentary
Coarse-grained Granite
Granitoid (Felsic Plutonic Rock)
igneous
Pebble (likely Siltstone or fine-grained Sandstone)
Sedimentary Clastic Rock
sedimentary
Sandstone (with potential fossil inclusions)
Clastic sedimentary rock (primarily SiO2)
sedimentary
Amber
Succinite (specifically for Baltic amber); C10H16O (Variable organic compound)
mineral
Limestone with Lichen/Moss
Calcium Carbonate (CaCO3)
sedimentary
Yellow Quartzite River Stone
Quartzite (SiO2)
metamorphic
Limestone (Fossiliferous)
Calcium Carbonate (CaCO3) - Bioclastic Limestone
sedimentary