Industrial Byproduct (Anthropogenic Material)

Tumbled sodalite (probable)

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂

Coal (Bituminous)

Organic sedimentary rock primarily consisting of carbon (C)

Sandstone (Weathered Pebble)

Arenite (SiO2 primarily)

Sandstone

Arenite (specifically Quartz Arenite)

Coal (Anthracite or Bituminous)

Lithified plant matter (Carbon)

Fossiliferous Limestone with Crinoid Stem fragment

Calcite (CaCO3) containing Crinoidea fossils

Unidentified metallic mineral or meteorite fragment

Indeterminate; possible native metal-bearing sulfide or iron meteorite fragment

Fossilized coral (possible)

Indeterminate fossil; the image does not show enough diagnostic detail to identify a taxon

Diamond (or Diamond Simulant)

Carbon (C) or Zirconium dioxide (ZrO2) for CZ

Small metallic meteorite fragment (probable stony-iron or iron meteorite)

Unclassified meteoritic material; exact classification requires chemical and petrographic testing

Man-made Metal Pin (Non-geological)

Antimony-Lead Alloy or Zinc/Brass Base with Electroplating

Polished brecciated jasper (likely)

Brecciated jasper, an opaque microcrystalline quartz (SiO₂) with contrasting silica-rich fragments and matrix

Red gemstone ring; likely synthetic ruby or red glass

Undetermined from the image; ruby is corundum (Al₂O₃), while red glass is amorphous silicate

Small dark pebble, possibly basalt or slag

Likely fine-grained mafic rock; exact identification requires examination

Diabase

Diabase (also known as Dolerite)

Mica Schist

Metamorphic Schist

Milky quartz

Quartz (silicon dioxide, SiO₂)

Mudstone

Lutylite (group of fine-grained sedimentary rocks)

Peridot ring

Gem-quality olivine, typically forsterite–fayalite solid solution ((Mg,Fe)₂SiO₄)

Quartzite

Quartzite (primarily SiO2)

Limestone

Sedimentary Calcium Carbonate (CaCO3)

Laterite (Red Clay)

Laterite (Fe2O3 · nH2O and Al2O3 · nH2O)

Quartzite

Quartzite (primarily SiO2)

Basalt (Weathered)

Extrusive Igneous Rock (Mafic composition)

Milky Quartz

Quartz (Silicon Dioxide - SiO2)

Diamond (or Cubic Zirconia simulant)

Carbon (C) or Zirconium Dioxide (ZrO2)

Gold-bearing quartz or ironstone fragment

Quartz (SiO₂) with possible native gold and iron oxides

Agate

Silicon Dioxide (Chalcedony), SiO2

Diamond

C (Carbon)

Dalmatian stone

Dalmatian jasper (commercial name); commonly spotted rhyolite or related feldspar-rich rock, not true jasper

Tumbled yellow quartz (likely citrine or iron-stained quartz)

Quartz, SiO₂; yellow color from trace iron or irradiation/heat-related coloration

Diamond

Carbon (C)

Carborundum

Silicon Carbide (SiC)

Blue tumbled glass-like specimen; likely blue slag glass

Likely man-made glass (silicate glass), not a natural mineral; exact material cannot be confirmed from the image

Faceted red gemstone, likely ruby

Corundum (Al₂O₃), colored red by chromium; identification from the image is uncertain

Likely sodalite (rough blue specimen)

Sodalite, Na₈(Al₆Si₆O₂₄)Cl₂

Dark rock fragment, possibly basalt

Undetermined; possibly basalt (fine-grained mafic volcanic rock)

Red cabochon gemstone, likely garnet

Likely almandine garnet, Fe₃Al₂(SiO₄)₃; identification from the image is uncertain

Orbicular jasper (often sold as leopard-skin jasper)

Silicified volcanic tuff/rhyolite; chiefly microcrystalline quartz and chalcedony (SiO₂), with iron oxides and altered volcanic minerals

Small rounded pebble

Indeterminate lithic grain; likely weathered sandstone, iron-stained quartz-rich rock, or a concretion

Diamond

Carbon (C)

Tumbled jasper (likely)

Microcrystalline quartz, SiO₂; likely jasper, a variety of chalcedony