Not A Natural Rock (Man Made Composite)

Smoky quartz fragment

Quartz, silicon dioxide (SiO₂), smoky variety

Pink Tiger's Eye

Silicified Riebeckite Asbestos (SiO2)

Hematite

Iron(III) oxide (Fe2O3)

Polished black obsidian pyramid/block

Obsidian — natural volcanic glass, chiefly rhyolitic silica (approximately 70–75% SiO₂)

White seed-bead gemstone strand, likely freshwater pearl or shell pearl

Pearl: nacreous calcium carbonate, chiefly aragonite (CaCO₃) in conchiolin; identification uncertain from image

Fossilized Coral (Petoskey-style)

Hexagonaria percarinata (Fossilized Rugose Coral)

Yellow Chert (Chalcedony)

Microcrystalline Quartz (SiO2)

Blue Dyed Quartzite

Silicon Dioxide (SiO2) with artificial pigment

Quartz (likely Chalcedony or Chert)

Silicon Dioxide (SiO2)

Amethyst

Silicon Dioxide (SiO2)

Chert (Brown Variety)

Microcrystalline Quartz (SiO2)

Red Quartzite

Quartzite (SiO2 with iron oxide impurities)

Cubic Zirconia

Zirconium Dioxide (ZrO2)

Yellow Quartz

Silicon Dioxide (SiO2)

Polished brecciated jasper

Jasper, opaque microcrystalline quartz (SiO₂), likely brecciated jasper with iron-oxide and dark silicate inclusions

Tumbled blue glassy mineral, possibly sodalite or blue aventurine

Identification uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) or blue-dyed quartz/slag-like material

Dyed Blue Agate

Silicon Dioxide (SiO2) with artificial cobalt-based dye

Quartzite

Silica (SiO2) quartzite

Tumbled quartz crystal (likely smoky or iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Amethyst

Quartz (Silicon Dioxide with iron impurities), SiO2

Citrine Quartz

Silicon Dioxide (SiO2)

Raw smoky quartz with dark mineral inclusions

Quartz (SiO₂), likely smoky quartz; dark inclusions may be chlorite, tourmaline, or iron/manganese oxides

Blue Topaz

Aluminum silicate fluoride hydroxide (Al2SiO4(F,OH)2)

Crinoid Stem Segment Fossil

Crinoidea (columnal ossicle)

Diamond (in jewelry)

Cubic Carbon (C)

Quartzite

SiO2 (Silicon Dioxide / Metamorphic Quartz)

Polished labradorite

Labradorite, calcium-rich plagioclase feldspar (approximately Ca0.5–0.7Na0.5–0.3Al1.5–1.7Si2.5–2.3O8)

Tumbled red jasper and blue-green turquoise (likely dyed or stabilized)

Red jasper: microcrystalline quartz, SiO₂, colored by iron oxides; turquoise: hydrated copper-aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Coquina

Biogenic Limestone (Coquina)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Polished blue chalcedony or glass-like quartz specimen

Chalcedony (microcrystalline SiO₂), possibly treated or synthetic; exact identification requires testing

Diamond

C (Native Carbon)

Chert / Flint

Silicon dioxide (Microcrystalline Quartz, $SiO_2$)

Fluorite Octahedron

Fluorite (Calcium Fluoride, CaF2)

Chert (often called Flint or Jasper)

Microcrystalline Quartz (SiO2)

Peacock ore (iridescent chalcopyrite, possibly bornite)

Chalcopyrite, CuFeS₂; the iridescent surface may be natural tarnish or artificial acid treatment. Similar material is bornite, Cu₅FeS₄.

Quartzite Pebble

Metamorphic Quartzite

Fossilized oyster shell

Bivalvia; likely an oyster (Ostreidae), partly mineralized with calcite

Chert (Flint)

Microcrystalline Quartz (SiO2)

Fossilized Shark Tooth (Sand Tiger)

Carcharias sp. (Fossilized Tooth)

Diamond (or high-refractive faceted gemstone)

Carbon; C

Citrine Quartz

Silicon Dioxide (SiO2) with trace Iron