Mineraloid (Human Made Geological Specimen)

Chert (Flinty variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Mixed mineral and rock specimen collection

Assorted silicates, carbonates, oxides, and sulfides; individual species cannot be reliably identified from this image

Tumbled quartz-rich pebble, likely milky quartz with iron-oxide staining

Quartz (SiO₂), possibly with hematite/goethite inclusions or surface coating

Black Obsidian

Volcanic Glass

Loose faceted colorless gemstones, likely quartz or glass-like mineral chips

Most consistent with quartz (SiO₂), though the photograph cannot exclude synthetic cubic zirconia or glass

Polished banded calcite (often sold as “onyx marble” or Mexican onyx)

Banded calcite; predominantly CaCO₃, usually microcrystalline to fibrous calcite

Chert (and Limestone)

Silicon Dioxide (SiO2)

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Green Glass (often marketed as 'Obsidian' or 'Green Quartz')

Amorphous Silica (SiO2) with copper or chromium additives

Gemstone bead necklace (likely citrine or yellow quartz)

Quartz, SiO₂; precise identification is uncertain because the beads are blurred and metal settings obscure them

Natural White Pearl

Calcium Carbonate (Aragonite/Calcite) with Conchiolin - CaCO3

Chert (containing Flint and Chalcedony)

Microcrystalline Quartz (SiO2)

Galena (lead sulfide)

Galena, PbS

Chert / Flint

Silicon Dioxide (SiO₂)

Chert (possibly a worked stone flake)

Microcrystalline quartz, SiO₂

Obsidian (likely black obsidian)

Volcanic glass; predominantly rhyolitic silica glass (SiO₂-rich)

Banded Chert / Chalcedony

Silicon Dioxide (SiO2)

Goldstone (Brown/Gold)

Aventurine Glass (Man-made glass with Copper inclusions)

Chert / Flint

Chert (varieties include Flint)

Gray sandstone or weathered volcanic rock

Likely quartz-rich sandstone; exact identification is uncertain from the image alone

Obsidian

Amorphous volcanic glass (primarily SiO2)

Iron-rich sandstone or weathered ironstone

Ferruginous sandstone; primarily quartz (SiO₂) cemented or stained by iron oxides, chiefly hematite (Fe₂O₃) and goethite (FeO(OH))

Chert Nodule

Cryptocrystalline quartz (SiO2)

Obsidian

Obsidian (Volcanic Glass)

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely opaque chalcedony/jasper

Likely iron-rich slag or weathered ironstone

Hematite–goethite-rich material (Fe₂O₃/FeO(OH)); possibly industrial iron slag

Milky quartz (likely rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Chalcedony with iron-oxide staining

Microcrystalline quartz (SiO₂), likely chalcedony or chert with limonite/goethite staining

Polymictic breccia, possibly volcanic breccia

Polymictic clastic breccia; likely a matrix-supported breccia containing lithic fragments, quartz, feldspar, and dark mafic minerals

Likely tumbled jasper or iron-rich chert

Microcrystalline quartz (SiO₂), potentially hematite/goethite-bearing

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Obsidian

Obsidian (Volcanic Glass, SiO2 + impurities)

Man-made Glass (Tumbled/Shaped)

Amorphous Silicon Dioxide (SiO2) with metal oxide colorants

Obsidian

Obsidian (Volcanic Glass; SiO2 content > 70%)

Opal cabochon or opal-like decorative specimen

Hydrated amorphous silica, SiO₂·nH₂O; likely synthetic or assembled opal material

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Chert Pebble/Nodule

Chert (a microcrystalline or cryptocrystalline sedimentary form of quartz, SiO2)

Blue Apatite

Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)

Tumbled brown quartz crystal (likely smoky quartz or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

White quartz-rich stone, possibly milky quartz or quartzite

Quartz (SiO₂), possibly microcrystalline quartzite

Tumbled pink-and-white quartz

Quartz, SiO₂; likely rose quartz with milky quartz

Iron-rich vesicular rock, possibly slag or weathered basalt

Identification uncertain; likely ferruginous basalt/ironstone, with possible anthropogenic iron slag