Mineral With Artificial Coating

Ironstone Matrix with Jasper / Chert

Ferruginous Chert / Limonitic Jasper (SiO2 with Fe-oxides)

Peridot (Olivine)

Olivine (Magnesium Iron Silicate), (Mg,Fe)2SiO4

Dyed Agate Slice

Silicon Dioxide (SiO2) - variety of Chalcedony

Smoky quartz (likely)

Quartz, silicon dioxide (SiO₂), naturally irradiated variety

Pink Dyed Agate

Silicon Dioxide (SiO2) with synthetic pigment

Quartz-rich feldspathic rock, possibly weathered granite or quartzite

Likely quartz and feldspar aggregate; exact identification is uncertain from the photograph

Unidentified brown mineral/rock fragment

Indeterminate from image; possibly iron-stained quartz, feldspar, or weathered limonite

Sandstone (River Rock)

Arenite (composed primarily of SiO2)

Scoria (vesicular volcanic rock)

Basaltic scoria; chiefly plagioclase, pyroxene, olivine, and volcanic glass

Dyed Blue Agate

Silicon Dioxide (SiO2) with artificial cobalt-based dye

Weathered stone, likely sandstone or altered volcanic rock

Indeterminate; possibly quartz-rich sandstone or weathered tuff

Purple Agate (Dyed Chalcedony)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Porphyritic Basalt (likely artificially dyed or altered)

Basalt with plagioclase phenocrysts (likely treated)

Tumbled red jasper

Jasper, microcrystalline quartz (SiO₂) colored mainly by iron oxides

Dyed Pink Agate Slice

Cryptocrystalline variety of Quartz (SiO2)

Quartz geode

Microcrystalline and crystalline quartz, SiO₂, likely with chalcedony and iron-oxide staining

Polished labradorite fragment

Labradorite, a calcium-rich plagioclase feldspar; approximate formula (Ca,Na)(Al,Si)₄O₈

Sandstone (Iron-stained)

Arenite with Limonite/Hematite staining

Quartz Druzy

Crystalline Silicon Dioxide (SiO2)

Citrine

Silicon dioxide (SiO2)

Weathered serpentinite (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, carbonate, and chromite

Polished leopard jasper (likely ocean jasper)

Silicified microcrystalline quartz/chalcedony; mainly SiO₂ with iron-oxide inclusions

Heat-Treated Citrine (Amethyst-based)

Quartz (Silicon Dioxide) - SiO2

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

White Quartz Sphere

Silicon Dioxide (SiO2)

Likely weathered iron-rich rock (possible limonite/goethite-bearing stone)

Limonite–goethite mixture, commonly approximated as hydrated iron oxides (FeO(OH)·nH₂O)

Dyed Selenite

Gypsum (Calcium Sulfate Dihydrate, CaSO4·2H2O)

Limonite (Iron Ore)

Limonite (FeO(OH)·nH2O)

Quartz–iron-oxide breccia or weathered quartz-bearing rock

Quartz (SiO₂) with limonite/goethite and possibly iron sulfides in a brecciated host

Weathered jasper pebble (probable red jasper/chert)

Microcrystalline quartz, SiO₂, colored mainly by iron oxides

Sandstone with Manganese Dendrites/Oxide coatings

Arenite with Pyrolusite and Romanechite (MnO2)

Oolitic Chert

Silicon Dioxide (SiO2) with Oolitic texture

Tumbled or naturally weathered quartz-rich stone, possibly iron-stained quartz

Quartz (SiO₂), with yellow-brown iron-oxide staining; exact identification is uncertain from the photograph

Iron-stained quartz

Quartz (SiO₂), likely with limonite/goethite inclusions

Sandstone (Pebble)

Sandstone (SiO2 with iron oxide impurities)

Likely tumbled quartz/chalcedony

Quartz (SiO₂), possibly milky quartz or pale chalcedony

Ferruginous Quartz (Iron-stained Quartz)

Silicon Dioxide (SiO2) with Iron Oxide inclusions (Fe2O3)

Quartz Druzy (on Geode Fragments)

Silicon Dioxide (SiO2)

Quartz-rich pegmatite or weathered feldspathic rock

Granite-family pegmatite; likely quartz (SiO₂) with feldspar and mica

Peridot (Olivine)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Tumbled quartz-rich pebble, possibly calcite or quartzite

Most likely microcrystalline quartz (SiO₂); carbonate identification would require testing

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxidized