Man Made Material, Not A Natural Rock Or Mineral Specimen

Chert (Chalky Flint Node)

Chert (Microcrystalline Quartz, SiO2)

Granite

Granite (phaneritic intrusive igneous rock consisting of quartz, feldspar, and mica)

Libyan Desert Glass

Tektite (high-silica impact glass), SiO2

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Asphalt Pavement (with aggregate)

Asphalt concrete

Sea Glass

Amorphous silicon dioxide

Bivalve shell fossil or modern shell

Calcareous bivalve shell, composed mainly of calcium carbonate (typically aragonite and/or calcite); species cannot be determined from this view

Carved yellow stone butterfly

Undetermined; possibly carved soapstone (talc-rich rock) or another soft ornamental stone

Beaded gemstone bracelet, likely lapis lazuli and pale quartz/agate

Lapis lazuli: lazurite-rich rock, chiefly (Na,Ca)₈(AlSiO₄)₆(S,SO)₂; pale beads are uncertain

Yellow cabochon gemstone, likely citrine or yellow glass imitation

Quartz (SiO₂), if natural citrine; visual evidence is insufficient to exclude man-made glass or resin

Opalite

Synthetic Opalised Glass

Sandstone Concretion

Septarian or Carbonate-cemented Sandstone Concretion

Diamond (in a jewelry setting)

Carbon (C)

Clear quartz fragment

Quartz (silicon dioxide, SiO₂)

Milky quartz (rough fragment)

Quartz, silicon dioxide (SiO₂)

Painted Sandstone

Sandstone (clastic sedimentary rock) with acrylic/artistic coating

Boxwork or Septarian Concretion

Septarian nodule / Boxwork weathering

Turquoise cabochon ring

Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

Clear quartz crystal

Quartz (silicon dioxide, SiO₂)

Quartz crystal (likely clear quartz)

Quartz, silicon dioxide (SiO₂)

Aventurine

Quartz containing inclusions of Fuchsite (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Green Slag Glass

Cullet (Amorphous Silicon Dioxide with impurities)

Tumbled black obsidian (likely)

Volcanic glass; chiefly silica-rich rhyolitic glass (SiO₂)

Fossil or modern bivalve shell

Calcium carbonate shell, likely aragonite (CaCO₃); exact species cannot be determined from the image

Chert (Arrowhead/Artifact Fragment)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartz-rich stone, possibly aventurine quartz or quartzite

Quartz (SiO₂), likely massive or microcrystalline; exact identification requires testing

Raw quartz crystal

Quartz (silicon dioxide, SiO₂), likely milky or included quartz

Weathered stone nodule or concretion

Unidentified lithic concretion; composition cannot be determined from the image

Dyed Blue Agate Slice

Silicon Dioxide (SiO2)

Polished white calcite sphere (identification tentative)

Calcite, CaCO₃

Diamond

Native Carbon (C)

Likely dyed or painted stone

Unidentified natural rock; vivid purple, orange, and pink coloration appears to be a surface coating or pigment, so the underlying rock cannot be reliably identified from the image.

Weathered iron-rich rock, possibly jasper or ironstone

Likely limonite/goethite-bearing siliceous rock; exact identification requires hardness and streak tests

Blue Sapphire (Synthetic or Man-made Glass Imitation)

Corundum (Al2O3) if natural; Lead-glass or Spinal if synthetic

Sandstone

Arenite (SiO2 primarily)

Sandstone

Clastic Sedimentary Rock

Dyed Agate / Painted Stone

Silicon Dioxide (SiO2) with artificial pigment

Cullet Glass (sometimes mistaken for Blue Obsidian or Slag)

Amorphous Silicon Dioxide (SiO2) with chemical additives (e.g., Cobalt for blue color)

Eroded Brick or Pumice-like Scoria

Vesicular Basalt / Scoria (Anthropogenic variant: Eroded Firebrick)

Vesicular basalt (probable iron-rich volcanic rock)

Basalt; chiefly plagioclase, clinopyroxene, olivine, and Fe-Ti oxides

Polished black stone, likely black obsidian

Obsidian (volcanic glass), chiefly silica-rich rhyolitic composition

Polished silver sheen obsidian heart

Obsidian (volcanic glass), primarily rhyolitic silica-rich glass