Shale with Siltstone layering
Sedimentary Clastic Rock (Mudstone/Shale)
sedimentary
Category
Not A Natural Rock
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Smelter Slag
Anthropogenic Silicate Slag
igneous
Scoria (Lava Rock)
Scoria (vesicular basaltic rock)
igneous
Blue Dyed Agate Geode Slice
Chalcedony (Silicon Dioxide, SiO2) with artificial cobalt/iron-based dye
mineral
Conglomerate
Conglomerate (clastic sedimentary rock)
sedimentary
Basalt with Scoria/Vesicular Texture
Vesicular Basalt (Iron-rich/Oxidized)
igneous
Gabbro Pebble (Polished Beach/River Stone)
Gabbro
igneous
Smoky Quartz (Tumbled)
Smoky Quartz (SiO2 - Silicon Dioxide)
mineral
Granite
Granite
igneous
Vein-filled Sedimentary Rock
Silicified sedimentary rock with quartz/calcite vein
sedimentary
Sandstone
Arenite
sedimentary
Granite Pebble
Phaneritic plutonic rock (SiO2 primary)
igneous
Granite
Felsic intrusive igneous rock (Granite)
igneous
Granite
Granite (Phaneritic intrusive igneous rock)
igneous
Sandstone
Arenite (Siliclastic sedimentary rock, primarily SiO2)
sedimentary
Sandstone Concretion
Arenaceous concretion (primarily SiO2 with Fe2O3 staining)
sedimentary
Slag
Metallurgical Slag
igneous
Green Aventurine
Quartz with Fuchsite inclusions (SiO2)
mineral
Rough Amethyst
Silicon Dioxide (SiO2) with Iron impurities
mineral
Amethyst
Silicon Dioxide (SiO2) with iron impurities
mineral
Dyed or treated turquoise-like tumbled stone
Likely turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O), though blue-green magnesite or howlite imitation is possible
mineral
Jasper Pebble
Silicon Dioxide (SiO2) - Microcrystalline Quartz with Iron Oxide Impurities
sedimentary
Dalmatian Stone
Peralkaline igneous rock containing quartz, feldspar, and arfvedsonite
igneous
Quartzite
Quartzite (SiO2)
metamorphic
Red Jasper (in Quartz/Chalcedony)
Silicon Dioxide (SiO2) with iron oxide inclusions
sedimentary
Granite
Granite (phaneritic felsic intrusive rock)
igneous
Obsidian
Volcanic glass
igneous
Green Aventurine
Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2
mineral
Yellow Quartz (Citrine or Yellow Jasper)
Silicon Dioxide (SiO2)
mineral
Conglomerate
Conglomerate (Sedimentary Clastic Rock)
sedimentary
Granite
Phaneritic Igneous Rock (Granitic)
igneous
Clear Quartz / Diamond (untested)
Silicon Dioxide (SiO2) or Carbon (C)
mineral
Polished citrine quartz point
Quartz, silicon dioxide (SiO₂), yellow-orange variety commonly sold as citrine; possibly heat-treated amethyst
mineral
Quartzite
Quartzite (predominantly SiO2)
metamorphic
Hag Stone
Perforated sedimentary rock (typically limestone, sandstone, or flint)
sedimentary
Mixed Quartz and River Pebbles (Stone Collection)
Mixed assortment containing mainly Silicon Dioxide (SiO2)
igneous, sedimentary, metamorphic, and mineral
Herkimer Diamond
Quartz (Silicon Dioxide - SiO2)
mineral
Fossiliferous Shale
Carbonaceous Shale (with potential plant/aquatic fossils)
sedimentary
Scoria (Lava Rock)
Scoria (Mafic Volcanic Rock)
igneous
Scoria (Red Lava Rock)
Scoria (Vesicular basaltic rock)
Igneous
Mixed tumbled stone collection
Assorted minerals, likely including quartz, jasper, agate, and possibly obsidian or hematite
mineral
Blue Agate (Dyed Chalcedony)
Silicon Dioxide (SiO2)
sedimentary