Organic Gem Material (Botanical)

Rough Diamond

Diamond (pure Carbon, C)

Gold-bearing quartz vein rock

Quartz (SiO₂) with probable native gold and iron-oxide minerals

Rough Diamond

C (Native Carbon)

Olivine (Peridot in gem form)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Tumbled coral fragment (likely white calcitic coral)

Calcium carbonate, primarily aragonite or calcite (CaCO₃); exact coral genus cannot be determined from the image

Sedimentary Rock (Limestone or Siltstone pebble)

Sedimentary rock fragment

Chert

Microcrystalline Quartz (SiO2)

Peridotite

Peridotite (primarily Olivine and Pyroxene)

Amethyst (rough crystal fragment)

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron-related impurities

Vesicular basalt (possibly scoriaceous basalt)

Basalt; predominantly calcium-rich plagioclase, clinopyroxene, and often olivine, with volcanic glass

Raw greenish beryl (probable aquamarine)

Beryl, Be₃Al₂Si₆O₁₈; blue varieties are aquamarine

Mixed river-worn rock and mineral collection

Mostly quartz/quartzite, feldspar-bearing granitoid, chert, and mafic volcanic rocks; exact species vary by pebble

Dark basalt fragment

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

Rhodonite-bearing metamorphic rock

Manganese-rich metamorphic rock, chiefly rhodonite (MnSiO₃), with quartz and manganese oxides

Dark basalt or fine-grained mafic rock

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

Rose quartz (likely)

Quartz, silicon dioxide (SiO₂), pale pink variety

Petrified Wood

Silicified Wood (SiO2)

Chert (Flint)

Silicon Dioxide (SiO2)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Tumbled greenstone pebble

Likely serpentinite or greenstone; exact identification requires testing

Raw reddish-brown mineral specimen, possibly garnet

Garnet-group silicate, commonly almandine (Fe₃Al₂Si₃O₁₂); identification is uncertain from the blurred image

Unidentified weathered rock fragments

Likely mixed silicate rocks; specific identification requires testing

Unakite-like granite with a white feldspar inclusion

Granite, chiefly quartz–feldspar–biotite; pale inclusion likely albite/orthoclase feldspar

Gneiss or Schist

Gneiss or Mica Schist with Garnet

Amethyst

Amethyst (Silica mineral, SiO2)

Tumbled white chalcedony (likely common opal or milky quartz)

Microcrystalline quartz, SiO₂; possibly hydrated silica opal, SiO₂·nH₂O

Weathered pegmatitic granite (likely biotite granite)

Coarse-grained granite dominated by quartz, potassium feldspar, plagioclase, and biotite; exact identification requires testing

Corundum (variety Ruby/Sapphire)

Aluminum Oxide (Al2O3)

Banded chert or siliceous shale

Microcrystalline quartz (SiO₂), possibly interbedded with carbonaceous or clay-rich shale

Chert Nodules in Limestone

Cryptocrystalline Quartz (SiO2) within Calcium Carbonate (CaCO3)

Black tourmaline (likely schorl)

Schorl, sodium–iron tourmaline: NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Quartz-rich rock, likely quartzite or milky quartz

Quartz (SiO₂); probable quartzite if the grains are interlocked

Dark river pebble, likely basalt

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

Weathered quartz-rich rock, likely quartzite or quartz vein

Quartzite; predominantly quartz (SiO₂), possibly iron-oxide stained

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely in a limonite/goethite-rich matrix

Anthracite Coal

Carbon (with trace impurities)

Sandstone

Sandstone (SiO2-dominated clastic rock)

Jasper

Silicon Dioxide (SiO2)

Jasper

Silicon dioxide (Microcrystalline quartz, SiO2)

Jasper

Microcrystalline Quartz (SiO2)

Chert / Flint

Silicon Dioxide (SiO2)

Chert (Nodule)

Microcrystalline Quartz (SiO2)