Rounded river pebble
Indeterminate; likely quartz-rich sandstone, chert, or weathered volcanic rock
sedimentary
Category
Anthropogenic (Man Made Industrial Deposit)
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Riverstone Quartzite (Iron-stained)
Quartzite (primarily SiO2 with Limonite/Goethite staining)
metamorphic
Amethyst (Tumbled Cabinet Stone)
Silicon Dioxide (SiO2) with iron impurities
mineral
Chert with Limestone
Silicon Dioxide (SiO2) in Calcium Carbonate (CaCO3) Matrix
sedimentary
Flint
SiO2 (Cryptocrystalline Quartz)
sedimentary
Chert or Jasper
Microcrystalline Quartz (SiO2)
sedimentary
Blue Sapphire
Corundum (Al2O3) with traces of Iron and Titanium
mineral
Silver (Jewelry form)
Native Silver (Ag)
mineral
Bumblebee Jasper
Calcite with Arsenic and Sulfur inclusions
sedimentary
Pink Sapphire
Corundum (Al2O3 with Chromium/Titanium/Iron traces)
mineral
Pyrulite (Pyrite / Chalcopyrite)
Iron Sulfide (FeS2) or Copper Iron Sulfide (CuFeS2)
mineral
Fossilized echinoid (sea urchin), likely a flint/chalk-associated test
Echinoid fossil; likely a regular echinoid such as Echinocidaris or related taxon, composed mainly of recrystallized calcite (CaCO₃)
fossil
Green Glass Cullet / Recycled Glass
Amorphous Silicon Dioxide (SiO2) with various metal oxides
Man-made Glass (Not a natural rock or mineral)
Tiger's Eye
Pseudomorph of Quartz after Crocidolite (SiO2)
metamorphic
Chert (Flint / Jasper)
Silicon Dioxide (SiO2)
sedimentary
Fossil Sea Urchin (Echinoid)
Echinoidea fossil (often replaced by silica or calcite)
fossil
Chert (Flint / Quartz Nodule)
Microcrystalline Quartz (SiO2)
sedimentary
Chert (variations include Flint)
Microcrystalline or cryptocrystalline Quartz (SiO2)
sedimentary
Dyed blue tumbled stone, likely howlite or magnesite
Howlite (Ca₂B₅SiO₉(OH)₅) or magnesite (MgCO₃), artificially dyed blue
mineral
Sulfur (Sulphur)
Sulfur (S8)
mineral
Sandstone
Arenite (composed primarily of SiO2)
sedimentary
Polished Picasso jasper
Silicified carbonate rock, commonly marketed as Picasso jasper; composition varies and is not a single mineral species
metamorphic
Ruby (Raw/Rough)
Corundum (Al2O3 with Chromium trace)
mineral
Tumbled howlite (probable)
Howlite, Ca₂B₅SiO₉(OH)₅
mineral
Chert (Nodule)
Chert (Alpha-Quartz, SiO2)
sedimentary
Chert (Flint)
Microcrystalline Quartz (SiO2)
sedimentary
Quartzite Pebble
Quartzite (SiO2)
metamorphic
Quartzite
Quartzite (SiO2)
metamorphic
Amethyst
Silicon Dioxide (SiO2)
mineral
Rutilated Quartz
Silicon Dioxide (SiO2) with Titanium Dioxide (TiO2) inclusions
mineral
Chert (Jasper/Flint variety)
Silicon Dioxide (SiO2)
sedimentary
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
mineral
Basalt
Basalt (containing plagioclase, pyroxene, and olivine)
igneous
Blue goldstone beads
Man-made aventurine glass (silica glass with metallic copper inclusions), not natural lapis lazuli
mineral
Almandine Garnet (weathered)
Almandine (Fe3Al2(SiO4)3)
mineral
Pearl
Biogenic CaCO3 (Aragonite and Calcite)
mineral
Diamond
Natural Diamond (Carbon, C)
gemstone
Tumbled sodalite with white calcite veining
Sodalite, Na8(Al6Si6O24)Cl2, commonly intergrown with calcite, CaCO3
mineral
Tumbled Agate
Silicon Dioxide (SiO2)
mineral
Corundum (Sapphire/Ruby in Matrix)
Aluminium oxide (Al2O3)
mineral
Slag (Industrial Byproduct)
Ferrous/Non-ferrous Silicate
igneous (artificial/anthropogenic)
Green Slag Glass
Amorphous Silica / Glassy Blast Furnace Slag
Mineraloid (Industrial byproduct)