Indeterminate

Fossilized bone fragment (probable large mammal limb bone)

Mineral-replaced or permineralized bone; exact taxon cannot be determined from the image

Small brown stone (indeterminate)

Unidentified; the image does not show enough detail for a reliable identification

Indeterminate metallic mineral fragments

Possibly pyrite, chalcopyrite, or metallic sulfide-bearing rock

Quartz-rich breccia or silicified rock

Microcrystalline quartz (SiO₂), with iron-oxide staining and possible feldspar/calcite fragments

Quartz-bearing dark mineral specimen

Quartz (SiO₂) on a dark host rock, possibly basalt or sulfide-rich ore

Tumbled beige stone, possibly quartz or calcite

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Quartz / Calcite Pebble (Indeterminate due to severe blur)

SiO2 (Quartz) or CaCO3 (Calcite)

Tumbled brown stone, likely quartzite or jasper

Indeterminate; probable quartz-rich aggregate (SiO₂), possibly brown jasper

Iridescent polished/tumbled stone (likely coated quartz or glassy synthetic material)

Indeterminate; possibly quartz (SiO₂) with an artificial iridescent coating

Iron-rich sandstone or lateritic pebble

Ferruginous sandstone; chiefly quartz (SiO₂) cemented by iron oxides such as hematite/goethite

Faceted amber-colored gemstone, possibly citrine

Unidentified transparent gem; citrine is quartz (SiO₂), but the image alone cannot confirm the material

Slate

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz

Likely raw amethyst with a tumbled pale-green stone

Amethyst: purple quartz (SiO₂); green specimen is uncertain, possibly fluorite or green quartz

Rounded quartz-rich pebble, likely sandstone or granitic-derived pebble

Indeterminate clastic rock; likely quartz-rich sandstone/conglomerate clast

Likely calcite or limestone fragment

Calcite (CaCO₃), possibly limestone dominated by calcite

Likely weathered jasper or iron-rich chert

Microcrystalline quartz (SiO₂), with iron-oxide staining

Likely tumbled white quartz or quartzite pebble

Quartz (SiO₂), possibly quartzite

Rounded sandstone pebble

Quartz-rich sandstone, likely arkose or lithic sandstone

Iron-rich rock, possibly limonite/goethite

Hydrated iron oxides/hydroxides, commonly limonite (FeO(OH)·nH₂O) with goethite (α-FeO(OH))

Likely blue calcite or aragonite fragment

Calcite (CaCO₃), possibly aragonite (CaCO₃)

Clear Quartz Sphere

Silicon Dioxide (SiO2)

Weathered quartz-rich pebble (tentative)

Likely quartz/chalcedony, SiO₂, possibly iron-stained

Iron-rich slag or limonite-bearing rock

Hydrated iron oxides, chiefly limonite/goethite (FeO(OH)·nH₂O); possibly industrial iron slag

Reddish-brown, iron-stained rock fragment

Indeterminate; possibly weathered porphyritic volcanic rock

Likely quartz-rich rock fragment

Indeterminate; possibly quartz-bearing granite or quartzite

Rounded quartz-rich pebble, possibly chert or quartzite

Indeterminate; likely microcrystalline quartz (SiO₂) or quartzite

Likely polished dark stone or mineral fragment

Indeterminate; possibly hematite, magnetite, or dark basalt

Probable iron-rich mineral or weathered rock fragment

Indeterminate; possibly limonite/goethite-bearing material

Rounded quartz-rich pebble

Chert or quartzite pebble (indeterminate from image)

Weathered sandstone or iron-rich sedimentary rock

Indeterminate siliciclastic sandstone, possibly ferruginous sandstone

Small weathered rock fragment

Indeterminate; possibly carbonate-rich sandstone or limestone

Fossilized ammonite

Ammonoidea (likely an ammonite; exact genus indeterminate)

Likely iron-rich rock or meteorite fragment

Indeterminate; possible hematite-/magnetite-bearing material

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing silicate rock

Probable weathered sulfide-bearing rock

Indeterminate; possibly pyrite- or chalcopyrite-bearing matrix

Weathered quartz-rich rock fragment

Indeterminate; likely quartz-bearing granitoid or quartzite

Rounded river pebble (likely weathered granite or metamorphic rock)

Indeterminate; possible granitic or quartz-rich lithology

White tumbled stone, likely quartz or calcite

Indeterminate; possibly quartz (SiO₂) or calcite (CaCO₃)

Possible fossilized shell or coral fragment

Indeterminate biogenic carbonate, likely calcite (CaCO₃)

Polished gray architectural stone panel

Indeterminate; likely polished granite or granitic gneiss

Fossilized bone or tooth fragment

Indeterminate fossil bone; possibly mammalian or reptilian

Small polished dark mineral specimen

Indeterminate; possibly black tourmaline (schorl) or hematite