Man Made Material, Not A Natural Rock Or Mineral Specimen

Ferrochrome Slag

Anthropogenic slag (Fe-Cr alloy waste)

Sandstone

Arenite (SiO2 based)

Mixed river-worn rock and mineral collection

Mostly quartz/quartzite, feldspar-bearing granitoid, chert, and mafic volcanic rocks; exact species vary by pebble

Diamond

Carbon (C)

Weathered quartz-rich pebble, possibly granitic gneiss

Quartz–feldspar–mica aggregate; likely granitoid or gneiss

Turquoise-style beaded bracelet

Turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O; possibly dyed or composite beads

Likely weathered granite or granitic gneiss fragment

Granite; primarily quartz, feldspar, and mica

Gold-bearing quartz or iron-stained quartzite

Quartz (SiO₂), possibly with native gold and iron oxides

Unidentified weathered mineral/rock fragment

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

Sandstone (Quartzose Sandstone)

Arenite

Likely polished rhyolite or porphyritic volcanic rock

Rhyolite, possibly flow-banded or altered rhyolite; composition mainly quartz and alkali feldspar with minor biotite/iron oxides

Likely rough green-blue glassy mineral fragment

Unidentified; the image is insufficient to distinguish a natural mineral from industrial slag or glass

Polished smoky quartz pendant

Smoky quartz, silicon dioxide (SiO₂), colored by irradiation-related defects

Likely weathered granite or granitic gneiss

Granite/granitic gneiss; chiefly quartz (SiO₂), feldspar, and dark mica or amphibole

Diamond (or Diamond Simulant)

Carbon (C)

Sandstone (Quartzite-rich)

Clastic Sedimentary Rock (primarily SiO2)

Sandstone (Quartzose type)

Arenite (primarily SiO2)

Small brown mineral or rock fragment

Undetermined; the image does not show enough diagnostic detail for reliable identification

Chert (Chalcedony/Agate)

Microcrystalline Quartz (SiO2)

Green aventurine pebble (likely)

Quartzite dominated by quartz (SiO₂), with green fuchsite mica inclusions

Sandstone (Quartz Sandstone)

Clastic sedimentary rock (primarily SiO2)

Landscaping river rock (mixed rounded pebbles)

Mixed lithologies; likely water-worn quartzite, granite, and other silicate pebbles

Rounded gray river pebble

Likely quartz-rich metamorphic or igneous pebble; exact identification requires testing

Pearl and Garnet Glass

Calcium Carbonate (CaCO3) for pearl; Silicon Dioxide (SiO2) for glass

Red jasper (likely)

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

Marine gastropod shell

Calcium-carbonate shell, primarily aragonite; species cannot be determined from the image

Diamond (Cut Gemstone)

Natural Carbon (C)

Pumice

Vesicular volcanic rock, primarily silica-rich volcanic glass (commonly rhyolitic or dacitic)

Goldstone

Man-made glass infused with copper crystals

Quartz (Engineered Quartz Surface)

Silicon Dioxide (SiO2) based composite

Sandstone (Banded)

Arenite (primarily SiO2)

Sandstone Concretion

Clastic Sedimentary Concretion (typically Quartz/Silica with Iron Oxide)

Smoky Quartz

Silicon Dioxide (SiO2)

Banded agate geode slice

Microcrystalline quartz (SiO₂), chiefly chalcedony with druzy quartz

Green Aventurine

Silicon Dioxide (Quartz with Fuchsite inclusions), SiO2

Granite (likely biotite granite or granodiorite)

Coarse-grained felsic intrusive rock composed mainly of quartz, feldspar, and mica; approximate composition: SiO₂-rich, with variable K-feldspar/plagioclase and biotite.

Green faceted gemstone earrings, likely synthetic emerald-colored glass or cubic zirconia

Undetermined; possible glass (amorphous silicate) or synthetic cubic zirconia (ZrO₂)

Sandstone (Quartz Arenite)

Sandstone (SiO2 with possible mineral cements)

Laterite

Fe2O3 and Al2O3 rich residual rock

Tumbled quartzite pebble (likely)

Quartz-rich quartzite; mainly SiO₂

Painted/tumbled stone specimens

Unidentified natural rock; likely a dark silicate stone and a weathered brown stone

Possible polished or tumbled stone

Unidentified; the image does not show enough detail to determine its composition