Organic Gem Material (Botanical)

Fossil Shark Tooth

Selachimorpha (Chondrichthyes dental fossil)

Garnet (Almandine)

Almandine (Fe3Al2(SiO4)3)

Petrified Wood

Silicified Wood (primarily SiO2)

Polished brecciated jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), with iron-oxide and possibly chlorite inclusions

Polished dendritic agate or jasper

Microcrystalline quartz (chalcedony), SiO₂, with iron-oxide inclusions

Amber

Succinates (Organic compound: C10H16O)

Quartz-rich pegmatite with green mica or chlorite

Granitic pegmatite; chiefly quartz (SiO₂), with feldspar and probable muscovite/chlorite

Chert (Flint)

Silicon Dioxide (SiO2)

Likely pink feldspar-bearing pegmatite

Quartz–feldspar pegmatite, likely containing pink potassium feldspar (KAlSi₃O₈) and quartz (SiO₂)

Likely quartz-rich rock or mineral fragment

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

Green aventurine (likely rough/tumbled quartzite)

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

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

Pearl necklace

Pearl—biogenic calcium carbonate, primarily aragonite (CaCO₃)

Raw green aventurine (likely)

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

Raw ruby (likely corundum)

Corundum, Al₂O₃; red color caused mainly by chromium

Chalcedony (Chert/Flint)

Silicon Dioxide (SiO2)

Likely coal (possibly anthracite)

Coal, composed chiefly of carbon-rich organic matter; rank cannot be confirmed from the photograph

Turquoise

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

Rhodonite

Manganese Silicate (MnSiO₃)

Fossiliferous Limestone with Fossil Fragment

Fossiliferous Limestone (CaCO3 with organic remains)

Polished green moss agate cabochon

Moss agate: microcrystalline quartz (SiO₂) with included chlorite/actinolite or iron-manganese minerals

Foliated metamorphic rock, likely mica schist

Muscovite–biotite schist with quartz and feldspar

Banded metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss (probable); exact identification requires testing

Petrified wood

Silicified wood, commonly quartz/chalcedony (SiO₂) replacing woody tissue

Yellow quartz (likely citrine)

Quartz, SiO₂; citrine is iron-colored quartz

Rounded iron-rich river pebble

Likely limonite/goethite-bearing rock; exact identification requires testing

Rounded pink granitic cobble

Granite, likely pink alkali-feldspar granite or granitic gneiss; primarily quartz, feldspar, and mica

Polished river pebble

Indeterminate; likely fine-grained quartz-rich sedimentary rock or weathered volcanic rock

Weathered basalt (possibly iron-stained volcanic rock)

Basalt; predominantly plagioclase, pyroxene, and possibly olivine, with iron-oxide staining

Dark igneous rock, likely basalt

Basalt; primarily plagioclase feldspar, pyroxene, and commonly olivine or iron-titanium oxides

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor iron-oxide and mica impurities

Quartz-bearing feldspathic rock fragment

Likely granitic pegmatite or quartz–feldspar vein material; predominantly quartz (SiO₂) and feldspar

Raw dark metamorphic rock, likely schist or slate

Mica schist or phyllite; commonly quartz–mica–chlorite aggregate

Tumbled chalcedony or agate

Microcrystalline quartz (SiO₂), likely chalcedony with iron-oxide staining

Tumbled river pebble, likely weathered basalt

Basalt; fine-grained mafic volcanic rock, commonly containing plagioclase, pyroxene, and iron oxides

Tumbled ruby-bearing corundum (probable)

Corundum, aluminum oxide (Al₂O₃), colored red by chromium; possibly ruby

Polished garnet-bearing gneiss

Biotite-quartz-feldspar gneiss with almandine garnet (garnet: Fe₃Al₂(SiO₄)₃)

Fossiliferous limestone, likely crinoidal limestone

Bioclastic limestone; predominantly calcite (CaCO₃), with possible dolomite and silicate impurities

Pegmatitic rose quartz with black tourmaline

Quartz (SiO₂) with schorl tourmaline (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄), likely feldspar and mica

Glauconitic Sandstone

Glauconitic Sandstone (Greensand)

Yellow faceted gemstone, likely citrine

Citrine: yellow variety of quartz, silicon dioxide (SiO₂)