Mineral And Sedimentary

Tumbled pale quartz (likely milky or citrine-like quartz)

Quartz, silicon dioxide (SiO₂)

Clear quartz cabochon or tumbled quartz

Quartz (silicon dioxide, SiO₂)

White quartz pebble

Quartz (silicon dioxide, SiO₂)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Hematite (Tumbled)

Iron(III) oxide (Fe2O3)

Polished magnetite-rich ironstone (possible magnetite pebble)

Magnetite, Fe₃O₄; possibly magnetite-bearing basalt or ironstone

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Iron-rich concretion or weathered ironstone

Limonite/goethite-rich iron oxide (hydrated FeO(OH)·nH₂O), possibly with hematite

Likely smoky quartz or quartz-rich tumbled fragment

Quartz, silicon dioxide (SiO₂), possibly smoky quartz

Tumbled jasper (likely brown jasper)

Microcrystalline quartz/chalcedony (SiO₂), colored mainly by iron oxides

Polished fossilized wood

Silicified wood (petrified wood), commonly quartz/chalcedony replacing wood

Tumbled quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Conglomerate

Clastic Sedimentary Rock

Milky quartz

Quartz (SiO₂), likely massive or microcrystalline quartz

Hematite (Iron Ore)

Hematite (Fe2O3)

Quartz crystal (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Likely quartz fragment

Quartz (silicon dioxide, SiO₂)

Clear quartz fragment

Quartz, silicon dioxide (SiO₂)

Tumbled quartz (likely rose quartz or included quartz)

Quartz, silicon dioxide (SiO₂)

Quartz cluster (likely druzy quartz)

Quartz, silicon dioxide (SiO₂)

Mixed mineral and rock specimen collection with an obsidian-like centerpiece

Likely black obsidian (volcanic glass), alongside quartz, amethyst, agate/jasper, and other tumbled minerals

Orange calcite

Calcite, calcium carbonate (CaCO₃)

Magnetite

Magnetite (Fe3O4)

Hematite

Iron(III) oxide (Fe2O3)

Polished red jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored mainly by iron oxides

Clear quartz (likely rough quartz crystal)

Quartz, silicon dioxide (SiO₂)

Specular Hematite (Specularite)

Iron(III) oxide (Fe2O3)

Mixed mineral and rock collection, including likely amethyst and assorted tumbled stones

Unidentified mixed specimens; visible purple quartz is likely amethyst (SiO₂)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Beach-worn fossil bone or coral fragment

Indeterminate biogenic calcium-carbonate material; likely fossilized bone (hydroxyapatite) or coral (calcite/aragonite)

Tumbled quartz (likely milky/rose quartz)

Quartz, silicon dioxide (SiO₂)

Tumbled quartz (likely milky quartz)

Quartz — silicon dioxide, SiO₂

Milky quartz / quartz vein fragment

Quartz, silicon dioxide (SiO₂)

Natural quartz crystal (likely herkimer-style quartz)

Quartz, silicon dioxide (SiO₂)

Milky Quartz

Silicon Dioxide (SiO2)

Quartz pebble or quartz-rich fragment

Quartz (silicon dioxide, SiO₂), possibly iron-stained or included

Weathered sandstone pebble

Quartz-rich sandstone, likely ferruginous sandstone

Siltstone

Siltstone (composed of mixed silicate minerals and clay)

Polished/tumbled brecciated jasper

Silica-rich microcrystalline quartz (chalcedony), commonly with iron-oxide minerals and assorted lithic fragments

Fossil-bearing concretion, possibly containing a fossil shell or other organic inclusion

Calcareous concretion; exact fossil and host-rock composition are not identifiable from the image

Fossiliferous Sedimentary Rock

Sedimentary limestone with invertebrate fossil imprint

Quartz

Quartz (SiO₂ - Silicon Dioxide)