Non Geological

Anthracite Coal

Carbon (with trace impurities)

Quartzite

Quartzite (SiO2)

Quartz / Quartzite

Silicon Dioxide (SiO2)

Synthetic Resin (Artificial Specimen)

Polyurethane or Polyester Resin

Gold

Native Gold (Au)

Likely polished dark stone or mineral specimen (unidentifiable from image)

Undetermined; possibly dark quartz-rich material, basalt, or obsidian

Painted Sandstone

Sandstone (clastic sedimentary rock) with acrylic/artistic coating

Obsidian

Volcanic Glass (70% or more SiO2)

Black Obsidian

Volcanic Glass (Silicon Dioxide with impurities)

Blue Goldstone

Aventurine Glass

Quartzite Pebble

Quartzite (primarily SiO2)

Green aventurine bead jewelry

Quartz (SiO₂), commonly with fuchsite or other mica inclusions

Man-made Blank Ammunition (Brass)

CuZn (Cartridge Brass - roughly 70% Copper, 30% Zinc)

N/A (Non-Geological Object)

Blue polished cabochon, likely dyed agate or chalcedony

Chalcedony (microcrystalline quartz, SiO₂); exact material cannot be confirmed from the image

Tektite (Indochinite)

Tektite (High-silica impact glass)

Sandstone with Liesegang Rings

Liesegang-banded Sandstone

Small polished, multicolored stone; exact identification is not possible from the image

Undetermined; it may be a naturally patterned stone such as jasper, but the visible colors alone are insufficient for identification

Concretion or weathered iron-rich rock

Likely limonite/goethite-rich concretion; exact identification requires testing

Fossil shell fragment (likely brachiopod or bivalve)

Indeterminate fossilized carbonate shell; likely Brachiopoda or Bivalvia

Libyan Desert Glass

Libyan Desert Glass (SiO2 with trace elements)

Pearl necklace with small blue-green gemstone accents

Pearls: nacre, chiefly aragonite (CaCO₃) and conchiolin; accents appear to be turquoise or similar opaque blue-green stone

Manganese-coated Sandstone

Clastic sedimentary rock with Manganese Oxide (often Pyrolusite or Psilomelane)

Anthracite Coal

Anthracite

Small dark pebble, likely basalt or iron-rich rock

Uncertain from image; possibly fine-grained basalt (mafic silicate rock)

Faceted purple-blue beads, likely synthetic glass or treated gemstone

Indeterminate; possible synthetic corundum, synthetic spinel, or dyed quartz (SiO₂)

Weathered agate or chalcedony nodule

Microcrystalline quartz (SiO₂), likely agate/chalcedony with iron-oxide staining

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

Anthropogenic textile material

Gold Ore in Matrix

Native Gold (Au) in Quartz/Limonite host rock

Tumbled brown banded agate beads

Agate, a banded variety of microcrystalline quartz (SiO₂)

Pearl-and-gemstone insect brooch

Pearl: nacre (aragonite, CaCO₃); colored stones are likely synthetic or natural corundum/spinel/glass, not determinable from the image

Green aventurine (tumbled)

Quartz, SiO₂, with fuchsite or other mica inclusions

Polished dark gemstone, likely hematite or magnetite

Hematite (Fe₂O₃) or magnetite (Fe₃O₄); exact identification requires testing

Blue Slag Glass

Amorphous Silica (Industrial byproduct)

Possible petrified wood or fossilized tooth

Unidentified silicified fossil; exact identification requires close examination

Green glassy mineral specimen, likely rough emerald or green fluorite

Tentatively beryl (Be₃Al₂Si₆O₁₈), emerald variety; synthetic/man-made glass cannot be excluded from the photograph

Glass / Silicon Dioxide (Man-made)

SiO2 (Amorphous Silicon Dioxide)

Obsidian

Obsidian (volcanic glass)

Rounded dark river stone

Likely basalt or fine-grained andesite; exact identification requires testing

Black Obsidian

Volcanic Glass (SiO2)

Tektite (Indochinite)

Impact Glass (SiO2 + Al2O3)

Rounded gray pebble, likely andesite or fine-grained basalt

Fine-grained volcanic rock; exact identification requires closer inspection