Anthropogenic Material

Slate

Metamorphic pelitic rock

Weathered, iron-stained bedrock (rock type uncertain)

Unidentified bedrock; orange-brown staining is likely iron oxides such as goethite and hematite

Amethyst

Quartz, SiO₂; purple coloration is associated with trace iron and natural irradiation.

Porous limestone pebble

Calcite-rich limestone (primarily CaCO₃); exact identification is uncertain from the image

Polished fossil coral agate

Silicified coral (chalcedony, SiO₂)

Green agate (likely dyed), used as jewelry beads

Microcrystalline quartz, SiO₂ (chalcedony; agate variety)

Likely quartz cabochon in a ring

Quartz (SiO₂), possibly clear or milky quartz; identification is uncertain from the photograph

Pearl necklace

Pearl, primarily aragonite (CaCO₃) and conchiolin

Polished banded calcite pendant (often sold as “onyx marble” or “banded onyx”)

Calcite, CaCO₃; trade name “onyx marble”

Likely slate

Slate, a fine-grained metamorphic rock composed mainly of mica-group minerals and quartz

Diamond (or Diamond Simulant)

C (Carbon) or synthetic equivalent

Diamond

C (Carbon)

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant

Chert or Chalcedony

Microcrystalline Quartz (SiO2)

Tektite

Natural impact glass

Chert

Microcrystalline quartz (SiO2)

Chert

Microcrystalline quartz (SiO2)

Chert

Microcrystalline quartz (SiO2)

Flint Nodule

Cryptocrystalline Quartz (SiO2)

Chert

Microcrystalline quartz (Silicon dioxide, SiO2)

Likely fossiliferous limestone fragment

Calcite-rich limestone, possibly containing fossil or shell fragments (primarily CaCO₃)

Milky quartz with iron-oxide staining

Quartz (SiO₂), likely massive to crystalline vein quartz

Amethyst (likely tumbled or cut)

Quartz, SiO₂; purple color typically from iron-related defects and natural irradiation

Flint

Silicon dioxide (SiO2)

Polished brown jasper

Jasper, an opaque microcrystalline variety of quartz (SiO₂), colored by iron oxides

Flint

Cryptocrystalline Quartz (SiO2)

Dendritic Opal

Hydrated amorphous silica with manganese oxide inclusions (SiO2·nH2O)

Flint

SiO2 (Cryptocrystalline Quartz)

Mixed gravel and small stones

Unsorted gravel; individual clasts are not identifiable from the image

Blue gemstone cross pendant

Likely faceted blue topaz (Al₂SiO₄(F,OH)₂); identification is uncertain from the image

Possibly a polished pale-green gemstone cabochon (likely aquamarine or fluorite)

Undetermined from the image; aquamarine is blue-green beryl (Be₃Al₂Si₆O₁₈), while fluorite is CaF₂

Red jasper (possible polished jasper pebble)

Jasper, an opaque variety of microcrystalline quartz (SiO₂)

Quartzite

Quartzite

Quartz-rich stone, possibly aventurine quartz or quartzite

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

Chert Pebble

Cryptocrystalline Quartz (SiO2)

Diamond

C

Diamond (or Diamond Simulant)

Carbon (C)

Chert (Flint)

Silicon dioxide (SiO2)

Chert/Flint nodule or weathered river rock

Microcrystalline or cryptocrystalline silica (SiO2)

Likely obsidian fragment

Volcanic glass; predominantly SiO₂ (amorphous, rhyolitic composition)

Iron Meteorite / Chondrite (Possible)

Extraterrestrial stony-iron or chondritic meteorite

Chert (Grey-Green Var.)

Silicon Dioxide (SiO2)