Organic Gem Material (Botanical)

Iron-stained quartzite or chert

Quartzite, predominantly SiO₂, with iron-oxide staining

Likely foliated metamorphic rock, possibly schist

Mica schist or micaceous quartzite; exact identification is uncertain from the photograph

Quartz-bearing granite or gneiss fragment

Granite/gneiss composed mainly of quartz (SiO₂), feldspar, and minor mica or ferromagnesian minerals

Apatite

Fluorapatite (Ca5(PO4)3F)

Olivine (Peridot)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Quartz (Iron-stained)

Silicon Dioxide (SiO2) with Hematite/Limonite impurities

Mixed rock and mineral collection

Mixed lithologies; likely quartz, feldspar, basalt, granite, chert, sandstone, and metamorphic rocks

Polished petrified wood

Silicified wood, primarily microcrystalline quartz (SiO₂) replacing cellular tissue

Green aventurine (likely rough/tumbled quartzite)

Quartzite dominated by quartz (SiO₂), colored by fuchsite mica or chlorite

Likely quartz-rich rock or mineral fragment

Quartz (SiO₂), possibly in a pegmatitic or granitic matrix

Tumbled lapis lazuli

Lapis lazuli; predominantly lazurite, (Na,Ca)₈(AlSiO₄)₆(S,SO)₄, with calcite and pyrite

Polished red gemstone pendant, likely red jasper or brecciated jasper

Jasper: microcrystalline quartz (SiO₂), commonly with hematite or iron-oxide inclusions

Tumbled yellow chalcedony (likely citrine or yellow quartz)

Quartz, SiO₂; potentially microcrystalline chalcedony

Jasper

Silicon Dioxide (SiO2)

Rough Diamond

Carbon (C)

Blue Apatite

Apatite (Calcium Phosphate) - Ca5(PO4)3(F,Cl,OH)

Rhodonite

Manganese Silicate (MnSiO₃)

Sandstone

Sandstone (Quartz-rich Arenite / SiO2)

Quartz-rich quartzite or silicified stone

Quartzite; predominantly microcrystalline quartz (SiO₂), with minor iron-oxide staining and possible feldspar/clay impurities

Fire Opal (in matrix)

Hydrated Silica (SiO2·nH2O)

Diamond

Carbon (C)

Polished blue chalcedony (likely blue quartz/chalcedony)

Microcrystalline quartz, SiO₂; blue color commonly from inclusions or coloration

Diamond

Carbon (C)

Chrysocolla

Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4 · nH2O)

Amethyst Geode

Amethyst (Silicon Dioxide), Formula: SiO2

Fossiliferous Sandstone with Plant Remains

Arenite with Carbonaceous impressions (likely Paleozoic/Mesozoic Flora)

Likely quartz-rich metamorphic rock (quartzite or quartz-veined schist)

Quartzite/siliceous schist; chiefly quartz (SiO₂), with probable mica and iron-oxide staining

Travertine

Terrestrial Sedimentary Limestone (CaCO3)

Quartz-rich sandstone (possibly arkosic sandstone)

Clastic sandstone composed mainly of quartz (SiO₂), with feldspar and mica fragments cemented by silica or carbonate

Vesicular basalt (possibly weathered scoria)

Basalt; chiefly plagioclase feldspar, pyroxene, and iron-rich minerals

Vesicular basalt (weathered lava rock)

Basalt, predominantly plagioclase, pyroxene, and minor olivine/iron oxides

Rounded dark volcanic rock, likely basalt

Basalt, a fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, with possible olivine

Milky Quartz with Iron Staining

Quartz (Silicon Dioxide, SiO2)

Likely yellow chalcedony or citrine cabochon

Cryptocrystalline quartz (chalcedony), SiO₂; alternatively quartz variety citrine

Raw Diamond

Carbon (C)

Honey calcite (optical calcite)

Calcite — calcium carbonate, CaCO₃

Gravel / Limestone Fragment

Calcium Carbonate (CaCO3) / Fine-grained Sedimentary Rock

Petrified Wood / Fossilized Bone

Silicified / Mineralized Fossil (Silica SiO2)

Fossil Shark Tooth

Carcharodon sp. (likely Otodus or similar Lamniformes order)

Tumbled orange chalcedony (likely carnelian)

Cryptocrystalline quartz, SiO₂; carnelian is orange-red chalcedony colored mainly by iron oxides

Rhodochrosite

Manganese carbonate (MnCO3)

Jasper

Silicon dioxide (SiO2) with impurities, microcrystalline quartz