Anthropogenic Material

Diamond

Carbon (C)

Rose quartz

Quartz, SiO₂ (rose-colored variety)

Flint (chert)

Microcrystalline quartz (SiO₂), a variety of chert

Chert (likely flint)

Microcrystalline quartz, SiO₂

Fossiliferous limestone pebble

Calcite-rich limestone (mainly CaCO₃), containing marine shell fossils

Granite or Pegmatite in host rock

Granitoid / Felsic Intrusive Rock

Basalt with pale mineral veins/coating

Likely vesicular or altered basalt, with calcite or zeolite minerals

Greenstone (Epidosite)

Epidosite (Metamorphosed Basalt/Diabase)

Weathered quartz-rich rock, possibly quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), identification uncertain from the photograph

Black onyx-style gemstone ring

Likely chalcedony (microcrystalline quartz, SiO₂), possibly dyed black; identification from the photo is uncertain

Andesite

Intermediate volcanic rock

Flint

Microcrystalline Quartz (SiO2)

Chert

Microcrystalline quartz (SiO2)

Fossil shell fragment

Indeterminate fossilized mollusk shell; species cannot be identified from the image

Chert (flint)

Microcrystalline quartz (SiO₂), commonly called chert; flint is a dark variety

Small purple crystal fragment, possibly amethyst

Quartz (SiO₂), variety amethyst; identification uncertain from the image

Travertine

Calcium Carbonate (CaCO3)

Diamond

Carbon (C)

Flint

SiO2 (Cryptocrystalline Quartz)

Small brown mineral or rock fragment

Undetermined; the image does not show enough diagnostic detail for reliable identification

Petrified Wood

Fossilized Xylem (SiO2)

Chert

Silicon dioxide (SiO2)

Diamond

C

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant (e.g., Cubic Zirconia ZrO2)

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant (e.g., Cubic Zirconia ZrO2)

Rhinestone (or glass crystal)

Silicon dioxide (if glass) / Various

Serpentine-rich serpentinite

Serpentinite, chiefly lizardite–chrysotile–antigorite Mg₃Si₂O₅(OH)₄, possibly with calcite and talc

Serpentinized ultramafic rock (likely serpentinite)

Serpentinite; chiefly antigorite/lizardite/chrysotile, commonly after peridotite (olivine–pyroxene)

Note: No specimen visible

Likely weathered quartz-rich stone or fossil fragment

Indeterminate; possibly quartz-bearing sandstone, iron-stained quartz, or a fragmentary fossil

Red garnet bead

Likely almandine–pyrope garnet, garnet-group silicate (approximately Fe₃Al₂Si₃O₁₂–Mg₃Al₂Si₃O₁₂)

Red bead-and-chain costume jewelry, likely glass or plastic

No geological identification; the red beads appear manufactured and cannot be identified as mineral from the image

Sea Glass

Man-made vitreous material

Sea Glass

Man-made vitreous material

Pink tourmaline rough crystals

Elbaite tourmaline, Na(Li,Al)₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Orbicular gneiss (likely augen gneiss)

Quartz–feldspar–biotite gneiss; locally termed augen gneiss

Mica-rich metamorphic rock, likely schist

Quartz–mica schist; commonly quartz with muscovite and/or biotite mica

Dark green metamorphic rock, likely serpentinite

Serpentinite, chiefly serpentine-group minerals (antigorite/lizardite/chrysotile), commonly with magnetite and chromite

Mica schist (likely biotite–muscovite schist)

Mica schist; chiefly quartz (SiO₂) plus muscovite and biotite mica, with possible garnet or graphite

Likely raw blue kyanite specimens

Kyanite, Al₂SiO₅

Siltstone

Siltstone (primarily SiO2 with various silicates)

Tumbled milky quartz pebble

Quartz (silicon dioxide, SiO₂)