Organic Gem Material (Botanical)

Blue sapphire

Corundum (Al₂O₃), blue variety colored mainly by iron and titanium

Chert (Flint Pebbles)

Chert (SiO2)

Gemstone rings (stones not reliably identifiable)

The pale stone may be quartz or another translucent gem; the red stone may be ruby, garnet, or synthetic corundum. Image detail is insufficient for identification.

Olivine (Peridotite)

Magnesium iron silicate (Mg, Fe)2SiO4

Polished green nephrite jade

Nephrite jade; interlocking tremolite–actinolite amphibole, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂

Amber

Succinate (Fossilized Tree Resin)

Diamond (Cut Gemstone)

Carbon (C)

Cabochon gemstone ring, likely smoky quartz or tourmaline

Unconfirmed quartz (SiO₂) or brown tourmaline (dravite); visual identification is inconclusive

Polished greenstone (likely serpentine or nephrite jade)

Serpentine-group mineral aggregate, commonly antigorite/lizardite; possible nephrite, a tremolite–actinolite amphibole aggregate

Pink microcline feldspar (likely amazonite-type feldspar)

Microcline, KAlSi₃O₈ (potassium feldspar)

Quartz-veined metamorphic cobble

Likely quartzite or quartz-rich metasedimentary rock; veins predominantly quartz (SiO₂)

Weathered iron-rich sandstone or lateritic rock

Ferruginous sandstone, primarily quartz (SiO₂) with iron oxides such as hematite/goethite

Quartz-rich pegmatitic rock, probably granitic gneiss

Quartz–feldspar–mica gneiss; locally pegmatitic granite

Likely blue-green kyanite crystal

Kyanite, Al₂SiO₅

Orange calcite (rough cleavage fragment)

Calcite, CaCO₃

Quartz-rich quartzite pebble

Quartzite (mostly SiO₂)

Vesicular basalt (likely scoria)

Vesicular basalt; chiefly plagioclase, pyroxene, and often olivine

Banded gneiss or gneissic schist

Quartz–feldspar–mica gneiss; exact mineral proportions require testing

Tumbled river pebble, likely basaltic andesite

Fine-grained mafic volcanic rock; composition likely plagioclase, pyroxene, and minor iron oxides

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar

Chlorastrolite (Isle Royale Greenstone)

Chlorastrolite (Pumpellyite-(Mg,Fe2+): Ca2MgAl2(Si2O7)(SiO4)(OH)2∙H2O)

Petrified Wood

Fossilized plant material (Silicon dioxide - SiO2)

Fossilized Bone

Petrified Bone / Biogenic Sedimentary

Olivine (Peridotite / Dunite Pebble)

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

Aquamarine (beryl) bead bracelet

Aquamarine, blue-green variety of beryl (Be₃Al₂Si₆O₁₈)

Boulder Opal (Koroit Matrix Opal Egg)

Hydrated Amorphous Silica (SiO2·nH2O) in Ironstone Matrix

Diamond

Carbon (C)

Banded Calcite (often sold as 'Green Onyx')

Calcite (Calcium Carbonate, CaCO3)

Rounded granite or granitic gneiss cobble

Granitoid, chiefly quartz, feldspar, and biotite/hornblende

Rounded greenish river pebble

Indeterminate; possibly weathered greenstone, basalt, or serpentinized ultramafic rock

Labradorite rough

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

Iron-stained quartz-rich cobble

Weathered granitic or quartz-feldspar rock; exact identification requires testing

Vesicular basalt (weathered volcanic scoria)

Basalt, predominantly plagioclase feldspar and clinopyroxene with possible olivine; vesicular texture

Vesicular basalt (possibly scoriaceous basalt)

Basalt, primarily plagioclase + clinopyroxene ± olivine; vesicles may be lined with secondary zeolites or calcite

Tumbled orange-brown feldspathic rock, likely granite or weathered syenite

Feldspar-rich granitoid; chiefly K-feldspar and plagioclase with minor quartz and dark biotite/amphibole

Conglomeratic breccia

Clast-supported polymictic conglomerate/breccia, cemented by silica- or carbonate-rich matrix

Pegmatitic granite

Coarse-grained granite, chiefly quartz, feldspar, and mica; likely a granitic pegmatite

Titanium Quartz (Aura Quartz)

Silicon Dioxide (SiO2) treated with Titanium

Limestone or Sandstone Cobble

Sedimentary rock (Calcium carbonate or Quartz based)

Turquoise in Matrix

CuAl6(PO4)4(OH)8·4H2O

Peridotite (Olivine Rock)

Peridotite (composed largely of olivine, (Mg, Fe)2SiO4)

Small polished amber or brown gemstone

Indeterminate from image; possibly amber (fossilized plant resin) or brown chalcedony/quartz