Mineraloid (Human Made Geological Specimen)

Pink opal

Common opal, hydrated amorphous silica (SiO₂·nH₂O), commonly colored by trace organic or iron compounds

Black Obsidian

Volcanic Glass (Amorphous Silicon Dioxide)

Polished yellow jasper or serpentine bead

Jasper: microcrystalline quartz (SiO₂); possible serpentine: Mg₃Si₂O₅(OH)₄

Obsidian

Volcanic glass

Black obsidian

Volcanic glass; predominantly rhyolitic silica-rich melt (approximately 70–80% SiO₂), lacking crystalline structure

Goldstone (Brown)

Aventurine Glass (Silicon Dioxide infused with Copper crystals)

Tumbled beige stone, possibly quartz or calcite

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Chert (Flint)

Silicon Dioxide (SiO2)

Banded sandstone pebble

Lithic or quartz-rich sandstone; exact composition requires testing

Weathered basalt column

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase, pyroxene, and commonly olivine

Polished blue stone, likely sodalite or dyed agate

Sodalite: Na₈(Al₆Si₆O₂₄)Cl₂; exact identification requires testing

Faceted clear gemstone, likely quartz or glass imitation

Most likely quartz (SiO₂); exact identification requires refractive-index and hardness tests

Chert (and Jasper/Chalcedony mixture)

Microcrystalline Quartz (SiO2)

Chert / Flint

Microcrystalline Quartz (SiO2)

Common Opal (Potch)

Hydrated Silica (SiO2·nH2O)

Black Obsidian

Amorphous volcanic glass (SiO2)

Man-made Synthetic Material (Plastic/Composite)

Acrylonitrile Butadiene Styrene (ABS) or High-Impact Polystyrene (HIPS)

Tumbled greenstone (likely serpentine or nephrite-like material)

Serpentine-group minerals, commonly antigorite/lizardite; possibly nephrite jade (actinolite-tremolite)

Chert (likely flint)

Microcrystalline quartz, SiO₂

Limonite (with Pyrite)

Limonite (Hydrated Iron Oxide) - FeO(OH)·nH2O

Clear quartz sphere or polished quartz cabochon (tentative)

Quartz, silicon dioxide (SiO₂); appearance may also be consistent with ordinary glass, which cannot be ruled out from the image alone

Opalite

Synthetic Opalite Glass / Opalized Glass

Likely flint (dark chert)

Microcrystalline quartz (SiO₂), commonly called chert or flint

Faceted clear gemstone in a gold-tone ring

Likely colorless quartz (SiO₂); the image does not establish the stone identity, and glass or another gem is possible

Chert

Microcrystalline quartz (SiO2)

Smoky Quartz

Smoky Quartz (Silicon Dioxide, SiO2)

Man-made Slag (Industrial Byproduct)

Anthropogenic Glassy Residue

Kidney Stone

Nephrolithiasis (Calcium Oxalate, Hydroxyapatite, or Uric Acid)

Chert

Microcrystalline quartz (SiO2)

Rounded quartz pebble

Quartz (silicon dioxide, SiO₂)

Decorative gemstone bracelet or jewelry

Unidentifiable from the blurred image; likely colored glass or synthetic stones, possibly mixed gemstone beads

Chert / Flint Handaxe

Cryptocrystalline Quartz (SiO2)

Fossil or modern bivalve shell

Calcium carbonate shell, likely aragonite (CaCO₃); exact species cannot be determined from the image

Pyrite

Iron Sulfide (FeS2)

Painted Garden Rock

Coated Siltstone or Mudstone

Polished black obsidian

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

Man-made Jewelry Charm (Enameled Metal)

Not a natural mineral; composed of base metal alloy (likely zinc or brass) and epoxy resin/enamel.

Polished black obsidian pyramid/block

Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)

Glass / Silicon Dioxide (Man-made)

SiO2 (Amorphous Silicon Dioxide)

Tumbled lavender quartz (likely lepidolite-bearing quartz or dyed quartz)

Quartz, SiO₂; possible lepidolite mica inclusions

Chert / Flint (Flaked Stone Tool / Projectile Point)

Microcrystalline Quartz (SiO2)

Chert (Arrowhead/Artifact Fragment)

Microcrystalline or Cryptocrystalline Quartz (SiO2)