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

Black obsidian

Volcanic glass, primarily rhyolitic silica glass (SiO₂-rich, noncrystalline)

Red jasper (likely tumbled/polished chalcedony)

Jasper, an opaque variety of microcrystalline quartz (SiO₂)

Polished sedimentary pebble, likely sandstone or quartzite

Quartz-rich sandstone (SiO₂-dominant), possibly weakly metamorphosed quartzite

Tumbled obsidian

Volcanic glass; chiefly silica-rich rhyolitic glass (approximately 70–80% SiO₂)

Possible tektite or iron-rich slag-like natural specimen

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

Jasper

Silicon Dioxide (SiO2) with impurities

Jasper

Silicon dioxide / Chalcedony (SiO2)

Orange Calcite point

Calcite (Calcium Carbonate, CaCO3)

Chalcedony Pebble

Cryptocrystalline Quartz (SiO2)

Small brown pebble or mineral fragment

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

Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Tumbled yellow jasper or chert

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

Dyed druzy quartz pendant

Quartz, SiO₂; likely a dyed druzy quartz cluster

Mixed polished/tumbled stones; likely blue calcite, red carnelian, and gray/blue quartz or agate

Probable calcite (CaCO₃), chalcedony/quartz (SiO₂), and iron-colored chalcedony

Chert (and Jasper) Nodules in Limestone

Silicon Dioxide (SiO2) microcrystalline quartz

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

Silicon Dioxide (SiO2) with Hematite inclusions

Ferrosilicon Slag (Industrial Vitrified Glass)

Vitreous Silicate Residue

Magnetic Hematite

Magnetized Hematite (an iron oxide mineral, Fe2O3, that has undergone magnetization)

Dyed Agate / Ruby Quartz

SiO2 (Silicon Dioxide)

Red Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Green Slag Glass

Cullet (Amorphous Silicon Dioxide with impurities)

Likely obsidian (black volcanic glass)

Obsidian; predominantly rhyolitic volcanic glass, mainly SiO₂

Uncertain polymict breccia or altered volcanic rock

Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing

Black glassy fragment, likely obsidian or industrial glass

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

Polished banded jasper (likely Picasso or scenic jasper)

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

Green aventurine (likely dyed quartzite)

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

Tumbled red/orange jasper

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

Small tumbled dark stone, possibly basalt or slag

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

Jasper / Chert Pebble

Microcrystalline Quartz (SiO2)

Dyed Pink Agate (Crackled)

Silicon Dioxide (SiO2) - Chalcedony variety

Likely tumbled sandstone or limestone

Quartz-rich sandstone (possibly calcarenite/limestone)

Tumbled brown banded jasper

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

Polished red jasper and carnelian-like stones

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

Likely tumbled dark volcanic rock

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

Jasper and Yellow Chert (Tumbled)

Microcrystalline Quartz (SiO2)

Weathered chert or jasper pebble

Microcrystalline quartz (SiO₂), likely opaque chert/jasper

Jasper Pebble

Microcrystalline Quartz (SiO2)

Goldstone

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

Man-made Polished Porcelain Tile (Artificial Geologic Lookalike)

Fused Silicate Ceramic with Alumina (Synthetic Kaolinite derivative)

Tumbled quartz pebble

Quartz, silicon dioxide (SiO₂), likely milky quartz

Red Jasper (with Quartz and Chert)

Silicon Dioxide (SiO2) with Iron Oxide inclusions

Red Jasper Pebble

Silicon Dioxide (SiO2) with Iron Oxide inclusions