Mineraloid (Human Made Geological Specimen)

Polished peach aventurine or quartz

Likely quartz (SiO₂), possibly feldspar-rich aventurine

Polished white chalcedony or milky quartz pebble

Chalcedony, microcrystalline quartz (SiO₂), possibly with iron-oxide staining or a minor mineral inclusion

Granite (weathered pebble)

Granite (plutonic igneous rock)

Opalite

Man-made Glass (Synthetic Opalized Glass)

Concrete fragment or Conglomerate

Artificial Conglomerate (Concrete) or Natural Conglomerate

Polished blue calcite sphere (tentative identification)

Calcite, CaCO₃; blue color generally results from trace impurities or inclusions

Painted Pet Rock (Quartzite/Sandstone base)

Silicon Dioxide (SiO2) with anthropomorphic acrylic embellishments

Chert (specifically a Lithic Flake)

Silicon Dioxide (SiO2) - Cryptocrystalline Quartz

Tumbled brown jasper (probable)

Microcrystalline quartz/chalcedony, SiO₂, with iron-oxide impurities

Granite

Granite (a plutonic rock)

Granite countertop

Commercial granite; likely a light-colored, quartz–feldspar-rich granite or granitoid

Polished mahogany obsidian (probable)

Volcanic glass; chiefly rhyolitic silica-rich glass (SiO₂), compositionally near rhyolite

Chert (varieties include Flint and Jasper)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Sea Glass

Amorphous silicon dioxide (SiO2) - Man-made glass tumbled by nature

Tumbled yellow chalcedony (likely silicified material)

Microcrystalline quartz, SiO₂; possibly iron-stained chalcedony or fossilized/silicified limestone

Chert or Jasper

Microcrystalline Quartz (SiO2)

Titanium-coated Metal Cube (Man-made Fidget Toy)

Titanium-anodized or electroplated alloy (e.g., Ti-coated Zinc or Aluminum)

Likely tumbled red mineral or glass imitation

Indeterminate; possibilities include red jasper (microcrystalline quartz, SiO₂) or dyed chalcedony

Polished agate bracelet (likely gray chalcedony)

Microcrystalline quartz, SiO₂; chalcedony/agate variety

Tumbled cream-colored pebble

Likely quartz-rich sandstone or limestone; exact identification requires testing

Pearl

Calcium Carbonate (mostly Aragonite), CaCO3 (with conchiolin)

Carved jasper bear figurine

Jasper, microcrystalline quartz (SiO₂), likely brecciated or orbicular jasper

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), probably rock crystal; exact identification is uncertain from the strongly backlit image

Flint

SiO2 (Cryptocrystalline Quartz)

Likely weathered metallic mineral or slag fragment

Indeterminate; possibly iron-rich sulfide/oxide material or industrial slag

Tumbled cream-colored mineral, likely calcite or quartz

Calcite (CaCO₃) or milky quartz (SiO₂); exact identification requires testing

Ring with an Orange Inlay

N/A (Man-made object)

Blue Goldstone

Aventurine Glass (Silicon Dioxide infused with Cobalt/Copper)

Goldstone

Aventurine Glass (Man-made)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Limonite (Iron Ore/Sandstone mixture)

Limonite (FeO(OH)·nH2O) often mixed with Goethite and sedimentary matrix

Inlaid stone ring (likely jasper or agate)

Likely microcrystalline quartz (chalcedony, SiO₂), possibly jasper, with decorative mineral inlays

Green glass cabochon or tumbled stone

Indeterminate; likely man-made glass, possibly aventurine glass rather than a natural mineral

Polished septarian nodule

Septarian concretion; calcite/aragonite and barite-filled fractures in a carbonate-rich mudstone, commonly with pyrite

Tumbled blue chalcedony (possibly blue agate)

Microcrystalline quartz, SiO₂; chalcedony variety

Asphalt (Road Aggregate)

Asphalt concrete / Bituminous mixture

Chert (Arrowhead Shard)

Microcrystalline silica (SiO2)

Blue calcite sphere

Calcite (CaCO₃), commonly blue-calcite variety

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Carved Stone Turtle

Carved Soapstone and Quartz

Fulgarite

Fulgurite (Lechatelierite / Vitrified Sand)

Goldstone (aventurine glass)

Man-made copper-bearing glass; not a natural mineral (commonly sold as blue/brown goldstone)