Anthropogenic (Man Made Material)

Limonite (Iron Ore)

FeO(OH)·nH2O

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

Weathered limestone or calcareous fossil fragment

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

Quartz–feldspar pegmatite specimen

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

Sandstone (Red Sandstone / River Stone)

Arenite (composed primarily of Quartz, SiO2, with Iron Oxide cementation)

Polished red banded stone, likely rhodonite

Rhodonite — manganese inosilicate, MnSiO₃; possibly rhodochrosite or dyed quartz

Polished hematite-rich ironstone

Hematite (Fe₂O₃), likely mixed with magnetite and iron-rich jasper

Green cabochon gemstone pendant, likely turquoise or dyed green turquoise

Probably turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O; exact identification requires testing

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Polished/tumbled multicolored stone, possibly jasper

Likely opaque microcrystalline quartz (chalcedony/jasper); exact identification is uncertain because the image is out of focus

Hag Stone

Perforated Sedimentary Rock (typically Limestone or Sandstone)

Petrified Wood

Silicified Wood (SiO2)

Breciated Limestone with Calcite Veins

Sedimentary Breccia (CaCO3)

Sandstone

Arenite (SiO2 principal)

Coarse-grained granite or granitic gneiss

Granite; primarily quartz (SiO₂), feldspar, and mica, possibly metamorphosed to gneiss

Chert (Flint variety)

Chert (Cryptocrystalline Quartz, SiO2)

Quartz-veined Limestone

Sedimentary limestone with quartz/calcite veinlets

Murex Fossil

Muricidae (Calcium Carbonate fossilization)

Weathered fossiliferous limestone

Bioclastic limestone, chiefly calcite (CaCO₃)

Chert (Jasper/Flint variety)

Microcrystalline Quartz (SiO2)

Rough turquoise-bearing rock (probable turquoise matrix)

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O, likely in a host-rock matrix

Milky Quartz

Silicon Dioxide (SiO2)

Massive Quartz

Silicon dioxide (SiO2)

Likely vertebra fossil or bone fragment

Indeterminate fossilized vertebra; mineralized hydroxyapatite, commonly Ca₅(PO₄)₃(OH)

Weathered limestone or calcitic fossil/reef fragment

Calcite-rich limestone (CaCO₃), possibly fossiliferous limestone

Polished blue chalcedony or glass-like quartz specimen

Chalcedony (microcrystalline SiO₂), possibly treated or synthetic; exact identification requires testing

Red Sandstone

Ferruginous Sandstone (SiO2 with Fe2O3)

Citrine Quartz / Yellow Quartz Pebbles

Silicon Dioxide (SiO2)

Brown chalcedony (likely carnelian/agate)

Cryptocrystalline quartz, SiO₂; iron-bearing chalcedony

Tumbled quartz pebble

Quartz (silicon dioxide, SiO₂)

Fossil-bearing sedimentary rock, possibly fossil wood or bone

Indeterminate silicified/carbonate fossil in sandstone or mudstone

Milky quartz

Quartz (silicon dioxide, SiO₂)

Chert (Flint Nodules)

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, possibly sandstone or quartzite

Likely quartzite (mostly SiO₂), though a granular sandstone is also possible

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with iron-oxide staining and minor feldspar or mica

Chert (often called Flint or Jasper)

Cryptocrystalline quartz (SiO2)

Likely weathered quartz-rich stone

Probably quartz-bearing sandstone or milky quartz; exact identification requires testing

Basalt River Pebble

Basalt

Diamond (or Simulant)

Carbon (C)

Diamond (Faceted)

Carbon (C)

Basalt (River Pebble)

Basalt