Organic Gem Material (Botanical)

Green beryl, possibly emerald

Beryl (Be₃Al₂Si₆O₁₈), green variety; emerald if chromium/vanadium-colored

Cantera Opal (Mexican Fire Opal in Rhyolite)

Hydrated silicon dioxide in rhyolitic volcanic matrix (SiO2·nH2O)

Weathered granite or granitic gneiss

Granite–gneiss, chiefly quartz, feldspar, and biotite/amphibole

Olivine-bearing peridotite (likely a small mantle-rock fragment)

Peridotite, chiefly olivine ((Mg,Fe)₂SiO₄), with possible pyroxene

Beryl crystal in a dark mica-rich matrix

Beryl, Be₃Al₂Si₆O₁₈; likely associated with biotite or schist

Metamorphosed mafic rock, likely amphibolite

Amphibolite, chiefly hornblende + plagioclase; possibly mafic gneiss or altered basalt

Tumbled amethyst

Amethyst, purple quartz (SiO₂), colored mainly by iron-related defects

Rounded river pebble (likely weathered sandstone or chert)

Indeterminate clastic sedimentary rock; possible quartz-rich sandstone

Fossilized coral (likely tabulate or colonial coral)

Fossil coral; possibly Hexagonaria or related Paleozoic colonial coral

Red-brown quartzite or quartz-rich sandstone

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with iron-oxide impurities

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), with possible feldspar, mica, and iron-oxide staining

Olivine-rich pebble (likely peridotite fragment)

Olivine, chiefly forsterite–fayalite solid solution; possible dunite/peridotite

Iron-stained quartzite or quartz-rich sandstone

Quartzite, predominantly SiO₂, with iron-oxide coatings (hematite/goethite)

Red sandstone fragment

Sandstone, likely quartz-rich ferruginous sandstone

Small rounded pebble (likely quartz or quartz-rich stone)

Uncertain; possibly microcrystalline quartz (SiO₂)

Weathered quartz-rich metamorphic rock, likely gneiss or quartzite

Quartz (SiO₂)-bearing gneiss; exact identification requires a fresh surface and tests

Weathered greenstone pebble

Metamorphosed mafic rock, commonly metabasalt or greenschist (exact identification requires testing)

Green tourmaline (likely elbaite)

Tourmaline group; likely elbaite, complex borosilicate such as Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Weathered quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂); likely quartzite if the grains are recrystallized and fused

Granite-like rounded cobble

Probably granitic rock, composed mainly of quartz, feldspar, and dark mafic minerals; exact identification is uncertain from the photograph.

Iron-rich quartzite or ironstone

Ferruginous quartzite; chiefly quartz (SiO₂) with iron oxides such as hematite and goethite

Weathered limestone or calcareous sandstone

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

Synthetic opal cabochon/bead

Opal-like hydrated amorphous silica; likely lab-created polymer–silica opal or Gilson synthetic opal (SiO₂·nH₂O)

Dyed Aura Quartz

Silicon Dioxide (SiO2) with metallic coating

Possible rough green tourmaline (verdelite)

Tourmaline group; commonly elbaite, Na(Li₁.₅Al₁.₅)Al₆Si₆O₁₈(BO₃)₃(OH)₄

Iron-stained quartz-rich rock, possibly jasperized quartz or quartzite

Mostly SiO₂ quartz with iron oxides/hydroxides (hematite, goethite) and possible clay or feldspar impurities

Polished tiger’s-eye

Chatoyant quartz, mainly fibrous crocidolite pseudomorphed by quartz (SiO₂)

Olivine (Peridot when gem-quality)

Magnesium Iron Silicate (Mg,Fe)2SiO4

Possibly biotite-rich mica schist or weathered mafic rock

Mica schist; chiefly biotite mica, quartz, and feldspar

Peridot (Olivine)

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

Faceted brown gemstone ring, likely smoky quartz

Smoky quartz (SiO₂), identification uncertain from the image

Blue-and-gold lapis lazuli fragment

Lapis lazuli; lazurite-rich calc-silicate rock (primarily lazurite, with calcite and pyrite)

Likely garnet crystal (rough fragment)

Garnet group; possibly almandine, Fe₃Al₂(SiO₄)₃

Colorless faceted gemstone, likely a diamond in a ring setting

Diamond (carbon, C); identification from the image is uncertain

Fossilized Shell Fragment / Mother of Pearl

Calcium Carbonate (CaCO3) - Aragonite/Calcite biomineral

Small greenish crystal/mineral fragment

Indeterminate; possibly olivine, quartz, or a green gemstone fragment

Garnet (Rough Almandine Crystal)

Almandine Garnet (Fe3Al2(SiO4)3)

Greenstone / Serpentinite Pebble

Serpentinite (Hydrated Magnesium Silicate, Mg3Si2O5(OH)4)

Turquoise

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

Weathered, veined rock fragment (likely granite or gneiss)

Probable granitic gneiss; quartz–feldspar–mica assemblage

Weathered iron-rich rock, likely magnetite-bearing basalt or ironstone

Basalt/ironstone mixture dominated by iron oxides, chiefly magnetite (Fe3O4) and hematite (Fe2O3)

Dark green-black stone, possibly serpentinite

Serpentinite (predominantly serpentine-group minerals; identification from photo is uncertain)