Man Made Material

Diamond

C

Diamond (or Diamond Simulant like Cubic Zirconia)

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

Polished black stone egg, probably black obsidian

Obsidian, a natural volcanic glass; composition primarily silica-rich glass (approximately SiO₂), with variable iron and other trace elements

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant (e.g., Cubic Zirconia ZrO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Sandstone Pebble

Sedimentary Clastic Rock (Quartz Arenite)

Sandstone

Sedimentary Clastic Rock

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone (Iron-stained)

Arenite (primarily SiO2 with Fe2O3 staining)

Sandstone

Arenite (primarily SiO2)

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Clastic sedimentary rock (primarily SiO2)

Quartz (possibly milky quartz)

Quartz (Silica; SiO₂)

Likely quartz-rich metamorphic rock (quartzite or milky quartz)

Quartzite; predominantly quartz (SiO₂), possibly with feldspar and iron-oxide staining

Likely weathered quartz-rich stone or fossil fragment

Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil

Staurolite-bearing mica schist (probable)

Mica schist composed chiefly of muscovite/biotite, quartz, and likely staurolite or garnet

Amethyst quartz cluster

Quartz, SiO₂; purple coloration from iron impurities and irradiation

Chert (Flint)

Chert (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert / Flint

Silicon Dioxide (SiO2)

Chert (Black Chert/Flint)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Fluorite

Fluorite (Calcium Fluoride, CaF2)

Rhodochrosite

Manganese Carbonate (MnCO3)

Rough amber-like brown mineral specimen

Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber

Sandstone with Manganese Dendrites

Arenite (mostly SiO2) with Manganese Oxide inclusions (MnO2)

Diamond (or Diamond Simulant)

C (Carbon) or synthetic equivalent

Weathered limestone or calcareous fossil fragment

Calcite-rich carbonate rock (CaCO₃), possibly fossiliferous limestone

Botryoidal hematite (speculative)

Hematite, iron(III) oxide (Fe₂O₃), possibly mixed with goethite or magnetite

Polished nephrite jade

Nephrite jade; compact amphibole aggregate, chiefly tremolite–actinolite, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Carved lavender chalcedony (likely agate) animal figurine

Microcrystalline quartz, SiO₂; probable chalcedony or pale lavender agate

Quartz–feldspar pegmatite specimen

Granitic pegmatite, chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), and mica-group minerals

Diamond

Carbon (C)

Coarse-grained granite or granitic pegmatite

Granite; primarily quartz (SiO₂), feldspar, and mica/amphibole

Dark mafic igneous rock, likely basalt or gabbro

Basalt–gabbroic rock; chiefly plagioclase feldspar and pyroxene, possibly olivine

Polished pink feldspar pebble

Orthoclase or microcline feldspar, KAlSi₃O₈; exact identification is uncertain from the image

Granite-like rock

Felsic intrusive igneous rock, likely granite or granodiorite

Quartz-veined Siltstone

Siltstone with Quartz (SiO2) veins

Turquoise

Hydrated phosphate of copper and aluminum, CuAl6(PO4)4(OH)8·4H2O

Quartz-rich feldspathic pebble, possibly granite or granitic gneiss

Quartz–feldspar aggregate, likely granite; dark inclusion may be biotite, hornblende, or iron-oxide staining

Pale blue-gray quartz-rich pebble (tentative)

Quartz, SiO₂, possibly chalcedony or a weathered metamorphic fragment