Mineraloid (Human Made Geological Specimen)

Polished dark river pebble

Likely fine-grained basalt or chert; exact identification requires testing

Milky quartz (likely tumbled or polished)

Quartz, silicon dioxide (SiO₂)

Tumbled chalcedony or quartz pebble

Microcrystalline quartz, SiO₂ (likely chalcedony; exact identification requires testing)

Banded calcite tower (often sold as “onyx” or honey calcite)

Calcite, CaCO₃

Tumbled polymictic stone, likely jasper-bearing conglomerate

Siliciclastic conglomerate with microcrystalline quartz (jasper/chert) and altered volcanic or feldspathic clasts

Milky quartz (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Blue Impression Jasper beads

Impression jasper (microcrystalline quartz/chalcedony), chiefly SiO₂, with iron-oxide and other mineral inclusions

Obsidian

Volcanic glass (SiO2 - Silicon Dioxide with impurities)

Goldstone

Avventurina (Cu + SiO2 glass)

Tumbled pale-green stone, likely prehnite or serpentine

Most consistent with massive prehnite, Ca₂Al₂Si₃O₁₀(OH)₂; serpentine is a possible alternative

Blue gemstone bead bracelet, likely lapis lazuli or dyed stone

Uncertain from image; possible lazurite-bearing lapis lazuli (Na₃Ca(Si₃Al₃)O₁₂S) or dyed quartz/glass imitation

Amber

Succinite (specific to Baltic amber), fossilized tree resin

Tumbled quartz-rich stone, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if metamorphic

Chert (and Limestone)

Silicon Dioxide (SiO2)

Bumblebee Jasper

Anhydrite-Aragonite mixture with Orpiment and Realgar

Fulgurite

Luechatelierite (SiO2 glass)

Polished dendritic agate or jasper

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

Mixed gravelly conglomeratic road aggregate

Polymictic clast-supported conglomerate or fill; composition varies, commonly quartz, feldspar, basalt, and weathered rock fragments

Amber

Succinite (C10H16O)

Petrified Wood

Silicified Wood (SiO2)

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

Chalk

Micrite (primarily Calcium Carbonate, CaCO3)

Yellow calcite cabochon

Calcite (calcium carbonate, CaCO₃), likely honey/yellow calcite

Chert (varieties include Flint and Mudstone)

Microcrystalline Silica (SiO2)

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

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

Chert (containing Flint and Chalcedony)

Microcrystalline Quartz (SiO2)

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

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

Banded calcite; predominantly CaCO₃, usually microcrystalline to fibrous calcite

Polymictic breccia, possibly volcanic breccia

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

Mixed mineral and rock specimen collection

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

Gemstone bead necklace (likely citrine or yellow quartz)

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

Limonite (Iron Ore)

Limonite (Hydrated iron oxide - FeO(OH)·nH2O)

Snowflake Obsidian

Spherulitic Volcanic Glass (SiO2 + impurities)

Chert / Flint

Chert (varieties include Flint)

Chert Pebble

Chert (Microcrystalline Quartz, SiO2)

Galena (lead sulfide)

Galena, PbS

Gray sandstone or weathered volcanic rock

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

Tumbled jasper or chert

Microcrystalline quartz (SiO₂), likely opaque chalcedony/jasper

Ethiopian Opal (Welo Opal)

Hydrated Amorphous Silica (SiO2·nH2O)

Chert (or Flint)

Microcrystalline quartz (SiO2)

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