Industrial Byproduct (Anthropogenic Material)

White Quartz Pebble

Crystalline Silicon Dioxide (SiO2)

Granodiorite (containing Biotite and Quartz)

Granodiorite (Plagioclase-rich phaneritic intrusive rock)

Likely weathered quartz-rich rock fragment

Uncertain; possibly quartz sandstone or a pale feldspathic rock

Fossil gastropod shell

Fossilized or mineral-replaced gastropod (class Gastropoda), exact genus indeterminate

Polished brecciated jasper

Jasper, microcrystalline quartz (SiO₂), commonly with iron-oxide impurities

Fossil coral or stromatoporoid fragment

Likely fossilized colonial coral; exact taxon indeterminate from image

Schist

Schist (Crystalline metamorphic rock)

Rounded yellow-brown cobble

Likely weathered sandstone or quartz-rich conglomeratic clast; exact identification requires a fresh surface and testing

Diamond (in jewelry setting)

Carbon (C)

Polished tiger’s-eye cabochon

Chatoyant quartz (SiO₂), typically quartz pseudomorphically replacing crocidolite fibers

Quartzite Pebble

Quartzite (SiO2 with minor impurities)

Quartz-rich geode or mineralized cavity in host rock

Likely a quartz-bearing geode; the pale crystals may be quartz (SiO₂), but the photo is not detailed enough for a firm identification.

Grey Quartzite Pebble

Quartzite (primarily SiO2)

Bituminous Coal

Bituminous coal (Lithotype: Durain/Clarain)

White Howlite (likely)

Howlite, Ca₂B₅SiO₉(OH)₅

Iron-stained quartz-rich rock, possibly jasperized quartz or quartzite

Mostly SiO₂ quartz with iron oxides/hydroxides (hematite, goethite) and possible clay or feldspar impurities

Fossil shell/brachiopod impression

Likely a fossil brachiopod (Phylum Brachiopoda), possibly a ribbed spiriferid; exact species requires examination

Likely weathered iron-rich quartz or chert

Microcrystalline quartz (SiO₂), possibly limonite/goethite stained

Tumbled jasper or iron-rich chert (uncertain)

Microcrystalline quartz, SiO₂, with iron-oxide inclusions

Chert (with Manganese Dendrites)

Chert (Cryptocrystalline Quartz, SiO2)

Polished ocean jasper / orbicular jasper (probable)

Silica-rich chalcedony (microcrystalline quartz, SiO₂) with iron oxides and altered volcanic inclusions

Tumbled jasper pebble

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

Cubic Zirconia (Faceted)

Zirconium dioxide (ZrO2)

Small dark mineral or rock fragment

Indeterminate; possibly mica-rich schist, biotite, or a dark sulfide mineral

Small tumbled quartz-like pebble

Likely quartz (SiO₂), possibly iron-stained chalcedony or feldspar

Yellow Ochre / Limonite

Limonite (Hydrated Iron(III) Oxide-Hydroxide, FeO(OH)·nH2O)

Likely tumbled lepidolite-bearing mica schist

Lepidolite-rich mica schist; chiefly lepidolite/muscovite mica, quartz, and possibly feldspar

Tumbled black stone, likely basalt or black jasper

Likely fine-grained basalt (plagioclase–pyroxene); exact identification requires testing

Diamond (Faceted)

Carbon (C)

Tumbled jasper (likely brown/yellow jasper)

Microcrystalline quartz, SiO₂, typically with iron-oxide and clay impurities

Rounded river pebble

Unidentified lithic pebble; exact rock type cannot be determined from the image

Polished brecciated jasper bracelet

Jasper, microcrystalline quartz (SiO₂), commonly with hematite and iron-oxide inclusions

Red jasper pebble (probable)

Jasper; microcrystalline quartz (SiO₂) colored mainly by iron oxides

Green aventurine bead

Quartz (SiO₂), usually quartzite containing fuchsite mica

Polished septarian nodule

Septarian calcite–aragonite nodule, commonly with chalcedony and iron-oxide minerals

Likely vesicular basalt

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase, pyroxene, and sometimes olivine

Polished leopard jasper (orbicular or brecciated jasper)

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

Rough Black Diamond (Bort / Carbonado)

Diamond (C)

Diamond

C (Carbon)

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)

Rough Diamond

Diamond (pure carbon, C)

Quartzite (or Milky Quartz pebble)

Quartzite (Metamorphosed Sandstone) / Silicon Dioxide (SiO2)