Chert (specifically White Chert or Flint)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Anthropogenic (Man Made Material Processed By Nature)
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Pyrite (Fool's Gold)
Iron Sulfide (FeS2)
mineral
Dumortierite in Quartz
Dumortierite (Al6O3(BO3)(SiO4)3) with Quartz (SiO2)
mineral
Quartz (possibly milky quartz or quartz with inclusions)
SiO2 (Silicon Dioxide)
Mineral
Snowflake Obsidian
Obsidian with Cristobalite inclusions (70–75% SiO2)
igneous
Blue Dyed Agate Geode (Slice)
Silicon Dioxide (SiO2) - Chalcedony / Quartz
mineral
Tumbled Stones (various)
Mixed Silica-based Minerals (primarily Quartz and Chalcedony)
mineral
Red Coral (Precious Coral)
Corallium rubrum (Calcium Carbonate, CaCO3)
sedimentary
Polished hematite-rich ironstone
Hematite (Fe₂O₃), likely mixed with magnetite and iron-rich jasper
mineral
Unidentified weathered rock fragments
Likely mixed silicate rocks; specific identification requires testing
mineral
Polished/tumbled multicolored stone, possibly jasper
Likely opaque microcrystalline quartz (chalcedony/jasper); exact identification is uncertain because the image is out of focus
mineral
Quartzite Pebble
Metamorphic Quartzite
metamorphic
Jasper (Yellow/Brown variety)
Silicon Dioxide (SiO2) with iron oxide impurities
sedimentary
Celestite (Celestine)
Strontium Sulfate (SrSO4)
mineral
Limestone
Sedimentary Calcium Carbonate (CaCO3)
sedimentary
Quartzite
Quartzite (SiO2)
metamorphic
Rose Quartz
Silicon Dioxide (SiO2)
mineral
Fossiliferous Limestone (Coquina / Shell Limestone)
CaCO3 (Calcium Carbonate)
sedimentary
Diamond
Carbon (C)
gemstone
Pallasite Meteorite
Pallasite (Stony-Iron Meteorite)
meteorite
Tumbled milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Pearl (with Peridot)
Calcium carbonate (CaCO3) + Conchiolin; Peridot: Magnesium iron silicate (Mg, Fe)2SiO4
mineral
Quartz (River Pebble)
Silicon Dioxide (SiO2)
mineral
Blue Cat's Eye Quartz (Heated/Dyed)
Silicon Dioxide (SiO2) with fibrous inclusions
mineral
Tumbled quartz pebble
Quartz (silicon dioxide, SiO₂)
mineral
Fossil-bearing sedimentary rock, possibly fossil wood or bone
Indeterminate silicified/carbonate fossil in sandstone or mudstone
fossil
Milky quartz
Quartz (silicon dioxide, SiO₂)
mineral
Chert (Septarian Nodules-like)
Silicon dioxide (SiO2)
sedimentary
Quartz vein in dark host rock
Quartz (SiO₂), likely in basalt, gabbro, or altered mafic rock
mineral
Chert
Microcrystalline Quartz (SiO2)
sedimentary
Gossan (Iron Hat) with Quartz and Chlorite
Limonite/Goethite-rich Gossan (FeO(OH)·nH2O) with inclusions of Quartz and Chlorite
Mineral/Metamorphic Substrate
Diamond
Carbon (C)
mineral
Mixed Mineral Bead Bracelet
Polycrystalline and Monocrystalline Silicates/Oxides (Quartz, Howlite, Hematite)
gemstone
Chert Breccia
Brecciated Chert (Microcrystalline Silica, SiO2)
sedimentary
Diamond (in Jewelry Setting)
Carbon (C) - Isometric-Hexoctahedral
mineral
Prehnite
Prehnite (Ca2Al2Si3O10(OH)2)
mineral
River Pebble Gravel
Hydrothermally modified Clastic Sediment (mainly Quartzite and Chert)
sedimentary
Banded Agate (Dyed)
SiO2 (Silicon Dioxide / Microcrystalline Quartz)
mineral
Ferruginous Sandstone
Clastic sedimentary rock (primarily Quartz with Iron Oxide cement)
sedimentary
Polished green aventurine
Quartzite dominated by quartz (SiO₂), colored by fuchsite mica and/or iron-bearing inclusions
mineral
Milky Quartz
Silicon Dioxide (SiO2)
mineral
Rose Quartz
Silicon Dioxide (SiO2) with traces of titanium, iron, or manganese
mineral