Chert (Jasper/Flint variety)
Microcrystalline or Cryptocrystalline Quartz (SiO2)
sedimentary
Category
Anthropogenic Specimen (Man Made)
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Flint (or Chert with cortex)
Silicon dioxide (SiO2)
sedimentary
Diorite (River Pebble)
Intermediate plutonic igneous rock
igneous
Chert (Common Variety, Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Likely iron-rich rock or weathered metallic mineral fragment
Uncertain; possibly limonite/goethite or iron-bearing slag
mineral
Dark rounded pebble, likely basalt or slag
Probable fine-grained mafic rock; possibly basalt (plagioclase–pyroxene) or industrial iron/steel slag
igneous
Chert (varieties include Flint and Jasper)
Silicon Dioxide (SiO2) - Microcrystalline Quartz
sedimentary
Tumbled greenstone (likely serpentinite or green jasper)
Serpentinite, commonly dominated by serpentine-group minerals (Mg₃Si₂O₅(OH)₄); exact identification requires testing
metamorphic
Chert Pebble
Chert (Microcrystalline Quartz, SiO2)
sedimentary
Blue goldstone beads
Man-made aventurine glass (silica glass with metallic copper inclusions), not natural lapis lazuli
mineral
Brown Chert
Microcrystalline Quartz (SiO2)
sedimentary
Ferrosilicon Slag (Industrial Vitrified Glass)
Vitreous Silicate Residue
Antropogenic (Man-made industrial byproduct)
Banded Sandstone
Arenite with Liesegang banding
sedimentary
Granite (Pegmatitic)
Phaneritic Felsic Igneous Rock
igneous
Tree Agate
Chalcedony (SiO2)
gemstone
Dyed Blue Agate Slice
Silicon Dioxide (SiO2)
mineral
Quartzite (River Pebble)
Quartzite (Mainly SiO2)
metamorphic
Chert (Iron-stained)
Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)
sedimentary
Carved Stone Turtle
Carved Soapstone and Quartz
mineral
Ferrochrome Slag
Industrial Glassy Slag (Fe-Cr alloy byproduct)
Antropogenic (Man-made industrial byproduct)
Cobalt Blue Sea Glass
Amorphous Silica Glass (SiO2 + CoO)
mineraloid / anthropogenic material
Chert (specifically Red Chert or Jasper)
Microcrystalline Quartz (SiO2)
sedimentary
Diorite (River Pebble)
Intermediate Phaneritic Igneous Rock
igneous
Petoskey Stone
Hexagonaria percarinata (Fossilized Rugose Coral)
sedimentary (fossilized)
Goldstone
N/A (Synthetic Glass with Copper Inclusions)
Manufactured Glass
Granite Pebble
Felsic intrusive igneous rock
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Chert (River Siltstone/Quartzite type)
Microcrystalline Quartz (SiO2)
sedimentary
Pyrite
Iron Disulfide (FeS2)
mineral
Pyrite
Iron Sulfide (FeS2)
mineral
Petrified Wood (Silicified Wood)
Silicified Paleoflora (mainly Quartz, SiO2)
metamorphic
Smoky Quartz
Smoky Quartz (Silicon Dioxide, SiO2)
mineral
Blue glass-like tumbled specimen
Most likely cobalt-blue slag glass or manufactured glass; not confidently identifiable as a natural mineral from the image
mineral
Chert (Jasper variety)
Silicon Dioxide (SiO2)
sedimentary
Chert (and/or Flint)
Chert (Cryptocrystalline variety of Quartz, SiO2)
sedimentary
Blue Slag Glass
Amorphous Silica (Byproduct of smelting)
Antropogenic (Man-made)
Granite
Granite (phaneritic felsic intrusive rock)
igneous
Diamond in Kimberlite
Diamond (C in Kimberlite)
igneous
Iron Slag
Iron smelting byproduct (Glassy/vesicular silicate)
anthropogenic / industrial byproduct
Pyrite in Matrix
Iron Sulfide (FeS2)
mineral
Quartz (Smoky Quartz variant)
Silicon Dioxide (SiO2)
mineral
Weathered iron-rich rock, possibly jasper or ironstone
Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests
mineral