Man Made Material

Gemstone Ring

Various (Likely Glass, Cubic Zirconia, or assorted semi-precious stones)

Sandstone (likely a river or beach pebble)

Sandstone (a clastic sedimentary rock)

Polished serpentine pendulum

Serpentine-group minerals, chiefly antigorite/lizardite; approximate formula Mg₃Si₂O₅(OH)₄

Amygdaloidal Basalt

Basalt with secondary mineral infillings (SiO2, (Ca,Na)2-3(Mg,Fe,Al)5Si8O22(OH)2)

Limestone

Calcium Carbonate (CaCO3)

N/A - Image does not contain a rock or mineral

Anthropogenic textile material

Dark river pebble, likely basalt or fine-grained volcanic rock

Basalt (probable); mostly plagioclase and pyroxene, with possible magnetite

Rounded pale quartz-rich pebble

Likely milky quartz or quartzite (SiO₂); exact identification is uncertain from the photograph

Iron-stained limestone or coral fragment

Calcite-rich carbonate rock; chiefly CaCO₃ (exact identification is uncertain from the image)

Tumbled jasper (likely ocean or orbicular jasper)

Microcrystalline quartz (chalcedony), SiO₂, with iron oxides and dark accessory minerals

Polished carnelian jasper / brecciated jasper

Microcrystalline quartz (SiO₂), chalcedony with iron-oxide pigments and opaque jasper fragments

Fossil shark teeth

Probably fossilized shark teeth, possibly *Otodus* or *Carcharhinus* species

Red Coral

Corallium rubrum (for precious red coral), although other species like Corallium japonicum and Paracorallium are also used.

Pyrite

Iron Disulfide (FeS2)

Vesicular basalt (likely weathered lava rock)

Vesicular basalt; primarily plagioclase feldspar, pyroxene, and volcanic glass, with possible iron-oxide alteration

Pink quartz bead necklace/strand

Quartz, silicon dioxide (SiO₂), likely rose quartz or pink chalcedony; exact identification is uncertain from the image

Polished banded agate slab or agate-look decorative stone

Microcrystalline quartz (chalcedony), SiO₂; exact identification is uncertain from the image

Quartzite

Quartzite (SiO2)

Chalcedony (Banded/Mottled Variety)

Chalcedony (a cryptocrystalline variety of Quartz, SiO2)

Brecciated jasper

Silica-rich cryptocrystalline quartz (SiO₂), commonly with iron-oxide and clay-rich matrix

Fossilized coral or porous marine limestone

Likely fossil coral (Scleractinia), composed mainly of calcite/aragonite (CaCO₃)

Tumbled basalt (likely)

Basalt; fine-grained mafic volcanic rock composed mainly of plagioclase feldspar and pyroxene, often with minor olivine and iron oxides

Rhinestone

Artificial Glass/Crystal

Pink-and-white quartz-rich rock, likely rose quartz or quartzite

Quartz (SiO₂), possibly rose-quartz-bearing quartzite; minor iron-oxide staining

Faceted blue gemstone, likely blue topaz or synthetic spinel

Topaz (Al₂SiO₄(F,OH)₂) or synthetic spinel (MgAl₂O₄); image insufficient for certainty

Vesicular basalt (likely weathered scoria)

Basaltic volcanic rock; chiefly plagioclase, clinopyroxene, and olivine with vesicles

Tumbled green gemstone, likely dyed howlite or serpentine

Most consistent with dyed howlite (Ca2B5SiO9(OH)5); exact identification requires testing

Mixed rock and mineral collection

Multiple specimens; visible pieces may include quartz, calcite, agate/chalcedony, jasper, and dyed or coated materials

Diamond

Carbon (C)

Quartz-rich pegmatitic rock (likely quartz–feldspar–mica specimen)

Granitic pegmatite; mainly quartz (SiO₂), feldspar, and dark mica/amphibole

Gray chalcedony (microcrystalline quartz)

Chalcedony, SiO₂; likely common gray/blue-gray variety

Chert (often called Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Iron Meteorite

Siderite (Iron-Nickel Meteorite)

Orange fire opal jewelry

Precious opal, hydrated amorphous silica (SiO₂·nH₂O)

Diamond

C

Granite

Intrusive Igneous Rock

Granite

Intrusive Igneous Rock

Banded Chert

Silicon Dioxide (SiO2)

Flint / Chert

Silicon dioxide (SiO2)

Quartz (River Pebble)

Quartz (SiO₂ - Silicon Dioxide)

Diamond

Diamond (pure Carbon, C)

Pink calcite (likely)

Calcite — calcium carbonate, CaCO₃