Industrial Byproduct (Anthropogenic Rock Like Material)

Polymictic conglomerate (possibly impact breccia)

Lithified polymictic conglomerate/breccia; clasts appear mainly mafic volcanic rock, with quartz- or feldspar-rich fragments in a dark matrix

Siltstone or Fine-grained Sandstone pebble

Siltstone (primarily SiO2 with clay minerals)

Sea Glass

Amorphous Silica (Anthropogenic glass) - SiO2

Andesite

Andesite (Intermediate Extrusive Volcanic Rock)

Chert (and Flint variant)

Microcrystalline Quartz (SiO2)

Jasper (Red Jasper)

Silicon Dioxide (SiO₂)

Diamond (or Diamond Simulant)

C (Carbon) or synthetic equivalent

Yellow Ochre / Limonite

Limonite (FeO(OH)·nH2O)

Quartz (Milky/River Quartz)

Silicon Dioxide (SiO2)

Chert (specifically Flint or Gray Chalcedony)

Microcrystalline Quartz (SiO2)

Vesicular Basalt (Lava Rock)

Vesicular Basalt

Milky Quartz or Calcite Pebble

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)

Botryoidal quartz (likely chalcedony/agate)

Microcrystalline silica, SiO₂; possibly quartz-rich chalcedony with iron-oxide staining

Green Glass Cullet / Recycled Glass

Amorphous Silicon Dioxide (SiO2) with various metal oxides

Polished orbicular jasper

Orbicular jasper; microcrystalline quartz (SiO₂) with hematite/goethite and other silicate inclusions

Chert / Flint

Microcrystalline quartz (SiO2)

Garnet Schist

Garnetiferous Mica Schist

Concrete Rubble with Aggregate

Hardened Portland Cement Paste with Coarse Aggregate

Limestone

Calcium Carbonate (CaCO3)

Chert (Flint)

Chert (SiO2)

Polished amber agate pendant/beads

Chalcedony (microcrystalline quartz), SiO₂, likely iron-stained yellow-orange agate

Greywacke (River Pebble)

Greywacke sandstone with quartz veining

Polished dark breccia or gneiss-like rock

Indeterminate polymictic breccia; likely quartz–feldspar–mica rock with iron-oxide staining

Red Sandstone

Clastic Sedimentary Rock (typically contains Quartz and Iron Oxide)

Botryoidal chalcedony (likely jasper/chalcedony aggregate)

Microcrystalline quartz, SiO₂; commonly iron-oxide stained

Obsidian-like volcanic rock (likely basaltic volcanic glass)

Basaltic obsidian or tachylite; composition chiefly volcanic glass with plagioclase and pyroxene

Red Sandstone

Arenite (with Iron Oxide / Hematite), Formula: SiO2 (Quartz) + Fe2O3 (Hematite coating)

Queen Conch Shell (Biogenic Calcium Carbonate)

Aliger gigas (synonym Strombus gigas); Composition: Aragonite (CaCO3)

Black glassy volcanic rock, likely scoria or obsidian

Vesicular basaltic scoria (probable); possibly dark obsidian

Chert (often called Flint or Jasper)

Silicon Dioxide (SiO2)

Copper-bearing altered rock, likely chrysocolla-bearing quartzite or breccia

Quartz (SiO₂) with copper silicate minerals, chiefly chrysocolla [approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O], and iron oxides

Diamond (Cut Specimen)

Diamond (pure carbon, C)

Fossil bivalve shell

Likely an extinct or modern-like ribbed cockle/scallop; exact genus requires locality and diagnostic hinge features

Polymer Clay (Mock Mineral)

Polyvinyl chloride (PVC) with plasticizers and pigment

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic volcanic rock; commonly basalt (plagioclase, pyroxene, and possible olivine)

Diabase (Greenstone)

Diabase (also known as Dolerite)

Quartz-rich mineral specimen, possibly druzy quartz with iron staining

Quartz (SiO₂), possibly coating a vesicular host rock

Botryoidal chalcedony with iron-oxide staining

Microcrystalline quartz (SiO₂), likely iron-oxide-bearing chalcedony

Weathered quartz-rich stone, possibly fossiliferous limestone

Indeterminate; likely calcite-rich limestone (CaCO₃) or weathered quartz-bearing rock

Rounded weathered stone, likely quartz-rich sandstone or fine-grained volcanic rock

Indeterminate hand specimen; probable quartz–feldspar sandstone (SiO₂-rich)

Sea Glass

Amorphous Silicon Dioxide (Man-made glass weathered by nature)

Quartzite

Quartzite (principally SiO2)