Mineraloid (Human Made Geological Specimen)

Chert

Microcrystalline Silicon Dioxide (SiO2)

Tumbled quartz (likely milky quartz)

Quartz — silicon dioxide (SiO₂)

Tektite (Indochinite)

Tektite (SiO2 + Al2O3)

Chert / Flint

Silicon Dioxide (SiO2)

Black Chert River Stone

Cryptocrystalline Quartz (SiO2)

Tumbled quartz-rich rock, possibly calcite or sandstone

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Blue apatite or dyed blue stone (likely apatite)

Apatite, Ca5(PO4)3(F,Cl,OH); exact identification is uncertain from the photograph

Dog (Sleeping)

Canis familiaris (or Canis lupus familiaris)

Riverstone (Sandstone Pebble)

Arenite (SiO2 with various lithic fragments)

White chalcedony cabochon ring

Chalcedony (microcrystalline quartz, SiO₂), likely white quartz variety

Common Opal

SiO2·nH2O (Hydrated Silicon Dioxide)

Likely tumbled quartz or calcite fragment

Probably quartz (SiO₂) or calcite (CaCO₃)

Chalcedony / milky quartz flake

Microcrystalline quartz (SiO₂), likely chalcedony; possibly a worked quartzite or chert fragment

Flint or chert

Microcrystalline quartz (SiO₂), commonly called flint when dark and nodular

White quartz pebble (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Green glass-like mineral specimen, likely fluorite

Fluorite (calcium fluoride, CaF₂), if natural; appearance may also indicate colored glass

Cut gemstone ring, likely diamond

Diamond (carbon, C), faceted gemstone; exact stone identification is uncertain from the image

Faceted Quartz (Rock Crystal)

Crystalline Silicon Dioxide (SiO2)

Tumbled smoky quartz

Quartz (SiO₂), likely smoky variety

Likely polished dark stone (identity uncertain)

Undetermined; possibly polished basalt, chert, or another dark silicate rock

Chert

Microcrystalline Quartz (SiO2)

Possible industrial slag or basaltic volcanic glass

Likely iron-rich vitreous slag; natural alternative: basaltic glass (tachylite)

Chert (or Flint)

Chert (cryptocrystalline quartz), SiO2

Jasper / Flint / Chert

Microcrystalline Quartz (SiO2)

Tumbled milky quartz (probable)

Quartz, silicon dioxide (SiO₂)

Likely tumbled quartz or calcite pebble

Quartz (SiO₂) or calcite (CaCO₃); exact identification requires testing

Biological Bone (Patella/Knee)

Patella (part of the Human Skeletal System)

Tumbled light-green quartz, likely aventurine or prehnite

Quartz (SiO₂), possibly green aventurine; visual identification is uncertain

Chert (Flint variety)

Chert (Microcrystalline or Cryptocrystalline Quartz), SiO2

Faceted clear quartz (rock crystal), likely a cut imitation or low-grade gemstone

Quartz, silicon dioxide (SiO₂)

Obsidian

Volcanic Glass

Chert Arrowhead (Projectile Point)

Microcrystalline Quartz (Chert or Flint)

Unidentified translucent crystal/mineral fragment

Likely quartz (SiO₂), but visual identification is uncertain

Tektite (Indochinite)

Impact Glass (SiO2 + Al2O3)

Chert (specifically White Chert or Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Green glassy gemstone-like specimen

Likely synthetic glass or treated quartz; exact identification requires testing

Chert (Flint Nodules)

Cryptocrystalline Quartz (SiO2)

Faceted colorless gemstone, likely cubic zirconia or diamond

Cubic zirconia (zirconium dioxide, ZrO₂) or diamond (carbon, C)

Gemstone ring, likely emerald and opal

Green beryl (Be₃Al₂Si₆O₁₈), with probable common opal (hydrated amorphous silica, SiO₂·nH₂O)

Rounded graywacke or sandstone cobble

Lithified clastic sandstone; likely quartz–feldspar–lithic grain aggregate in a silica or calcite matrix

Chert Arrowhead

Chert (Cryptocrystalline variety of Quartz, SiO2)

Blue Goldstone

Aventurine Glass