Mineraloid (Man Made)

Likely mica-rich schist (possibly phyllite)

Muscovite–biotite schist; exact identification requires examination of a fresh surface

Tumbled feldspar, likely orthoclase

Potassium feldspar (KAlSi₃O₈), likely orthoclase

Tumbled blue-green stone, likely chrysocolla or dyed chalcedony

Probable chrysocolla (hydrated copper aluminosilicate; variable composition), though appearance could also represent dyed chalcedony

Diamond

Diamond (pure Carbon, C)

Weathered quartz-rich rock, likely vein quartz

Mostly silicon dioxide (SiO₂); exact rock type cannot be confirmed from the photograph

Sandstone

Sedimentary Rock (Quartz Sandstone)

Brick veneer, likely manufactured from clay-rich shale

Fired clay brick; chiefly aluminosilicate minerals, commonly mullite and glassy silicate phases after firing

Sandstone

Arenite (primarily SiO2)

Diamond

Carbon (C)

Diamond (or Diamond Simulant)

Carbon (C) or Cubic Zirconia (ZrO2)

Diamond (or Cubic Zirconia)

Carbon (C) or Zirconium Dioxide (ZrO2)

Basalt

Basalt

Chert (varietal: Flint/Jasper)

Silicon Dioxide (SiO2)

Unidentified gray stone/concrete-like fragment

Indeterminate; likely a fine-grained carbonate or cementitious geological fragment

Asphalt aggregate (crushed stone in bitumen)

Artificial composite; predominantly crushed granite, basalt, limestone, and/or recycled aggregate bound by bitumen

Tumbled green aventurine (probable)

Quartzite dominated by quartz (SiO₂), with green mica/fuchsite or chlorite inclusions

Faceted clear gemstone in a gold-tone ring, likely colorless glass or cubic zirconia

Undetermined; possible cubic zirconia (ZrO₂) or glass (amorphous SiO₂)

Malachite

Malachite, Cu₂CO₃(OH)₂; a banded botryoidal copper carbonate specimen

Diamond

Diamond (pure Carbon, C)

Porous iron-rich rock or slag-like material

Unidentified; possibly limonite/goethite-rich ironstone

Diamond

Carbon (C)

Diamond

C (Pure Carbon)

Quartzite

Metamorphic Quartzite

Sandstone

Clastic sedimentary rock (primarily SiO2)

Sandstone (Quartzose)

Arenite (primarily SiO2)

Snowflake Obsidian

Volcanic Glass (spherulitic Obsidian) - SiO2 (with Cristobalite inclusions)

Arrowhead made of Moss Agate

Silicon Dioxide (SiO2) with manganese/iron inclusions

Fossilized Shell in Limestone

Biogenic Limestone (Calcium Carbonate, CaCO3)

Diamond in Kimberlite

Diamond in Kimberlite Matrix (Diamond: C, Kimberlite: complex Potassic Peridotite)

Chert (Siltstone / Flint)

SiO2 (Cryptocrystalline Quartz)

Diamond (likely) in an antique gold ring

Diamond, crystalline carbon (C)

Limestone

Sedimentary Rock (Primarily CaCO3)

Fossilized Coral (Coquina/Limestone)

Cnidaria Anthozoa (Fossilized)

Obsidian (volcanic glass), likely black obsidian

Rhyolitic volcanic glass; predominantly amorphous SiO₂

Tumbled black stone, likely black obsidian

Obsidian — natural volcanic glass, primarily SiO₂

Weathered chert or chalcedony nodule

Microcrystalline quartz (SiO₂), possibly silicified limestone or agate-like chalcedony

Diamond-drill core, likely dark mafic volcanic rock

Unidentified fine-grained mafic igneous core; exact lithology cannot be determined from the photograph

Polished labradorite

Labradorite, calcium-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

Polished serpentinite pebble

Serpentinite; primarily serpentine-group minerals (Mg3Si2O5(OH)4), with possible magnetite and talc

Basalt

Basalt (Mafic volcanic rock)

Quartzite

Quartzite (Metamorphosed Sandstone)

Quartzite

Metamorphic Quartzite (SiO2)