Industrial Byproduct (Anthropogenic Material)

Polished dragon blood jasper

Jasper, a microcrystalline variety of quartz (SiO₂), colored by iron oxides and other inclusions

Colorless faceted gemstone, likely quartz

Quartz (SiO₂), probably rock crystal; exact identification is uncertain from the strongly backlit image

Polished/tumbled rhodonite-rich stone

Rhodonite (MnSiO₃), likely mixed with quartz and manganese oxides

Unidentified weathered mineral/rock fragment

Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen

Diamond

C (Carbon)

Polished tektite (likely indochinite)

Impact glass; natural silica-rich glass, approximately SiO₂ 70–80%

Unidentified pale green mineral fragment

Possibly serpentine, jade, or green quartz; image insufficient for confident identification

Polished mahogany obsidian (likely)

Volcanic glass; primarily silica-rich rhyolitic glass (SiO₂), with iron oxides

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Sandstone

Arenite (SiO2 based with quartz grains)

Bronze or iron-age decorated pottery sherd

Archaeological ceramic fragment; likely fired clay with impressed or molded decoration, not a natural rock

Sandstone (Quartzose Sandstone)

Clastic Sedimentary Rock (Lithic arenite / Quartz arenite)

Diamond

Diamond (pure Carbon, C)

Diamond (in Jewelry)

Carbon (C)

Polished ocean jasper (orbicular jasper)

Jasper, microcrystalline quartz (SiO₂), commonly with iron oxides and chalcedony

Diamond (or Diamond Simulant like Cubic Zirconia)

Carbon (C) - if Diamond; Zirconium dioxide (ZrO2) - if Cubic Zirconia

Tumbled chalcedony (likely pale agate or common opal)

Microcrystalline quartz, SiO₂; possibly hydrated silica, SiO₂·nH₂O, if opal

Coal (Bituminous / Anthracite)

Carbonaceous Sedimentary Rock (C)

Iron-stained quartz-rich rock, possibly weathered granite or pegmatite

Quartz–feldspar rock with iron-oxide alteration; exact identification is uncertain from the photograph

Sea Glass

Amorphous Silica (SiO2) with various additives

Unidentified metallic mineral or meteorite fragment

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

Peach moonstone (polished/tumbled feldspar)

Orthoclase feldspar, KAlSi₃O₈ (possibly with albite intergrowths)

Rounded river pebble, likely quartz-rich sandstone or weathered granite

Indeterminate lithic clast; probable quartz–feldspar aggregate with iron-oxide staining

Pink feldspar fragment (likely orthoclase or microcline)

Potassium feldspar, KAlSi₃O₈

Tumbled green aventurine (probable)

Quartz (SiO₂), commonly with fuchsite mica inclusions

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Tumbled blue-green stone, likely aventurine or serpentine

Quartz-rich aventurine (SiO₂) or serpentine-group mineral; exact identification requires testing

Dyed blue tumbled stone, likely howlite or magnesite

Howlite (Ca₂B₅SiO₉(OH)₅) or magnesite (MgCO₃), artificially dyed blue

Quartzite Pebble

Quartzite (SiO2)

Peridot (Olivine)

Olivine ((Mg, Fe)2SiO4)

Sandstone

Arenite (Sandstone)

Basalt Pebble

Basalt (Mafic volcanic rock)

Quartzite

Quartzite (primarily SiO2)

Likely petrified wood or silicified fossil fragment

Silicified wood; predominantly microcrystalline quartz (SiO₂)

Quartz with Iron Staining

Silicon Dioxide (SiO2) with Hematite/Limonite inclusions

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