Sedimentary (If Natural Jasper) Or Artificial (If Slag)

Polished banded jasper (likely Picasso or scenic jasper)

Microcrystalline quartz (SiO₂), with iron oxides and other mineral impurities

Small brown pebble or mineral fragment

Indeterminate from image; possibly iron-stained quartz, ironstone, or a dark mineral grain

Tektite (specifically Indochinite)

Tektite (Natural silica glass)

Smoky Quartz

Silicon Dioxide (SiO2)

Tumbled red/orange jasper

Jasper, microcrystalline quartz (chalcedony; SiO₂) with iron-oxide impurities

Jasper (Chert)

Silicon Dioxide (SiO2)

Jasper with Hematite

Silicon Dioxide (SiO2) with Ferric Oxide (Fe2O3)

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Weathered chert or jasper pebble

Microcrystalline quartz (SiO₂), likely opaque chert/jasper

Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

Chert (and Jasper) Nodules in Limestone

Silicon Dioxide (SiO2) microcrystalline quartz

Bismuth

Bismuth (Bi)

Tumbled brown banded jasper

Microcrystalline quartz (SiO₂), commonly chalcedony with iron-oxide inclusions

Citrine

Quartz (SiO2) - specifically, a variety of macrocrystalline quartz

Jasper and Yellow Chert (Tumbled)

Microcrystalline Quartz (SiO2)

Uncertain polymict breccia or altered volcanic rock

Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing

Likely tumbled dark volcanic rock

Probably basalt or basaltic andesite; exact identification is uncertain from the image

Jasper pebble (possibly Red Jasper or Lake Superior Agate/Jasper mix)

Silicon Dioxide (SiO2) with Hematite inclusions

Man-made Polished Porcelain Tile (Artificial Geologic Lookalike)

Fused Silicate Ceramic with Alumina (Synthetic Kaolinite derivative)

Jasper and Agate Beads (Mahogany Obsidian, Dyed Agate, Turquoise/African Turquoise)

Silicon Dioxide (SiO2) mixture with inclusions / Hydrated Copper Aluminum Phosphate

Jasper

Silicon Dioxide (SiO2) with impurities

Jasper

Silicon dioxide / Chalcedony (SiO2)

Possible tektite or iron-rich slag-like natural specimen

Uncertain; possibly natural glass (tektite) or magnetite-rich rock

Likely smoky quartz pendant

Smoky quartz, silicon dioxide (SiO₂), quartz variety colored by irradiation-related defects

Polished red jasper and carnelian-like stones

Jasper: microcrystalline quartz (SiO₂), commonly colored by iron oxides; translucent piece may be carnelian, a chalcedony variety

Dyed Agate

Agate (Cryptocrystalline Quartz), SiO2

Red Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Likely obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂

Dyed agate (likely dyed chalcedony)

Microcrystalline quartz, SiO₂ (chalcedony/agate)

Goldstone

Not a natural mineral or rock. It is an ornamental glass.

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely iron-stained jasper/chalcedony

Smoky Quartz

Silicon Dioxide (SiO2)

Green aventurine (likely dyed quartzite)

Quartzite, predominantly quartz (SiO₂), colored by fuchsite mica or artificial dye

Red Jasper (in Quartz/Chalcedony)

Silicon Dioxide (SiO2) with iron oxide inclusions

Blue Dyed Agate

Cryptocrystalline Quartz (SiO2)

Polished brown jasper (likely ocean or brecciated jasper)

Microcrystalline quartz/chalcedony, SiO₂, colored mainly by iron oxides

Small tumbled dark stone, possibly basalt or slag

Likely fine-grained basalt; exact identification is uncertain from the photograph

Red Jasper (with Quartz and Chert)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Red Jasper Pebble

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Copper-bearing quartz/rock fragment with attached mica

Chalcopyrite-bearing quartz or altered igneous rock; attached flake likely muscovite or biotite mica

Tumbled amber-colored chalcedony or jasper

Microcrystalline quartz (SiO₂), likely iron-stained chalcedony/jasper