Anthropogenic Material

Chert

Microcrystalline Quartz (SiO2)

Opalite glass sphere (likely synthetic imitation)

Man-made opalescent glass; not natural opal

Polished serpentine (likely bowenite/antigorite)

Serpentine-group minerals, chiefly antigorite or lizardite: Mg₃Si₂O₅(OH)₄

Diamond (or Cubic Zirconia)

Cubic Carbon (C) or Zirconium Dioxide (ZrO2)

Muscovite Mica

Muscovite (Potassium Aluminum Silicate Hydroxide), KAl2(AlSi3O10)(OH)2

Chert (Flint)

Silicon Dioxide (SiO2)

Diamond (Set in Jewelry)

Carbon (C)

Tumbled snowflake obsidian

Obsidian (volcanic glass), commonly with cristobalite spherulites

Porphyritic basalt or andesite pebble

Porphyritic volcanic rock; commonly plagioclase phenocrysts in a fine mafic-to-intermediate matrix

Tiger's Eye

Silicon Dioxide (Quartz with crocidolite inclusions), SiO2

Blue Apatite

Ca5(PO4)3(F,Cl,OH)

Diamond

C

Chert (Flint)

Microcrystalline Quartz (SiO2)

Chert / Flint

Silicon dioxide (SiO2)

Likely basalt with a pale mineral-filled vesicle

Vesicular basalt, probably containing calcite or zeolite (uncertain from image)

Travertine

Calcium Carbonate (CaCO3)

Banded Chert

Silicon Dioxide (SiO2)

Flint / Chert

Silicon dioxide (SiO2)

Chalky Limestone

Carbonate sedimentary rock (CaCO3)

Chert (Nodule)

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Chert (often called Flint when found in chalk)

Microcrystalline Quartz (SiO2)

Chert (Jasper/Agate variety)

Microcrystalline Quartz (SiO2)

Chert (specifically Flint)

Silicon Dioxide (SiO2)

Blue glassy mineral fragment, possibly dyed/cobalt-colored calcite or aragonite

Uncertain from image; vivid blue coloration may indicate treated calcite (CaCO₃), aragonite (CaCO₃), or synthetic glass

Likely quartz-rich metamorphic rock (quartzite or milky quartz)

Quartzite; predominantly quartz (SiO₂), possibly with feldspar and iron-oxide staining

Sandstone

Arenite

Tumbled labradorite

Labradorite, a calcium-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

Likely polished black-and-white stone fragment

Indeterminate from image; possibly tourmalinated quartz, black-and-white jasper, or coated stone

Unidentified weathered mineral/rock fragment

Indeterminate; likely a weathered iron-rich silicate or sulfide-bearing specimen

Serpentinite (serpentine-rich metamorphic rock)

Serpentine-group minerals, chiefly antigorite, lizardite, and chrysotile; commonly with magnetite and minor brucite

Serpentine-rich rock (likely serpentinite)

Serpentinite; chiefly antigorite, lizardite, or chrysotile Mg₃Si₂O₅(OH)₄

Tumbled dark green stone, likely serpentine or greenstone

Serpentinite (hydrated magnesium silicate minerals, chiefly antigorite/lizardite); possible chlorite-rich greenstone

Brecciated quartzite (likely iron-stained quartz vein material)

Quartzite; predominantly quartz (SiO₂), with dark iron/manganese-oxide or mica-rich seams

Moldavite

Tektite

Chondrite Meteorite

Ordinary Chondrite (L, LL, or H type)

Fossilized Shark Tooth (Partial) or Coprolite

Elasmobranchii (fossil) or Coprolite (trace fossil)

Graphite

Graphite (Carbon, C)

Jasper

Microcrystalline Quartz (SiO2)

Jasper

Microcrystalline Quartz (SiO2)

Shark Tooth Fossil

Carcharocles megalodon or similar extinct shark tooth

Jasper

Microcrystalline quartz (SiO2)

Brown Quartz (Jasper or Chert)

Silicon Dioxide (SiO2)