Biogenic Material

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Iron-rich chert or jasper fragment

Microcrystalline quartz (SiO₂), colored by iron oxides/hydroxides

Likely weathered quartz-rich stone or fossil fragment

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

Flint (chert), likely chalcedony-rich variety

Microcrystalline quartz, SiO₂; flint is a dense cryptocrystalline form of chert

Micaceous schist (likely quartz–mica schist)

Quartz–mica schist; chiefly quartz (SiO₂), muscovite/biotite micas, with possible feldspar and accessory iron oxides

Unidentified gray stone/concrete-like fragment

Indeterminate; likely a fine-grained carbonate or cementitious geological fragment

Small weathered stone, possibly quartz-rich sandstone

Indeterminate siliciclastic rock; likely quartz-bearing sandstone or chert fragment

Small rounded pebble, likely weathered sandstone or iron-rich rock

Indeterminate; possibly quartz-rich sandstone (SiO₂) with iron-oxide staining

Tumbled chert or chalcedony pebble

Microcrystalline quartz (SiO₂), likely chert/chalcedony

Siltstone

Siltstone (composed of clastic quartz and feldspar grains)

Quartz Pebble

Silicon Dioxide (SiO2)

Botryoidal chalcedony (likely agate/jasper matrix)

Microcrystalline quartz, SiO₂; commonly containing iron-oxide impurities

Tumbled blue stone, likely blue aventurine or dyed quartz

Quartz (SiO₂), possibly with fuchsite inclusions; exact identification requires testing

Rounded iron-stained quartzite or sandstone pebble

Quartzite, predominantly SiO₂, with iron-oxide staining

Weathered iron-rich rock, likely laterite or ironstone

Ferruginous laterite/ironstone, composed mainly of goethite (FeO(OH)), hematite (Fe₂O₃), and clay minerals

Siltstone

Siltstone (composed of microscopic quartz and clay minerals)

Sandstone (likely Quartzose Sandstone pebble)

Arenite (primarily SiO2)

Quartzite pebble

Quartzite (SiO2)

Quartzite

Quartzite (composed primarily of SiO2)

Bull Quartz (White Quartz)

Silicon Dioxide (SiO2)

Serpentinite (likely)

Serpentinite, dominated by serpentine-group minerals (antigorite, lizardite, chrysotile), commonly with magnetite and relic olivine/pyroxene

Pink tourmaline rough crystals

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

Turquoise cabochon or turquoise-bearing material

Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O

Note: No specimen visible

Crushed Granite / Landscaping Gravel

Granitoid

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)

Red garnet bead

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

Brick fragment (Man-made material)

N/A (Fired clay)

Blue-green copper mineral-bearing rock, likely chrysocolla with malachite

Chrysocolla (hydrated copper aluminosilicate, approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O) with malachite (Cu₂CO₃(OH)₂), possibly in altered host rock

Iron-rich laterite or limonite/goethite concretion

Hydrated iron oxides, chiefly goethite (α-FeO(OH)) and limonite (FeO(OH)·nH₂O)

Chalcedony (Chert/Flint)

Silicon Dioxide (SiO2)

Blue-green botryoidal mineral specimen, likely chrysocolla or chrysocolla-bearing quartz

Chrysocolla (hydrated copper phyllosilicate; variable composition, commonly approximated as (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O)

Dalmatian jasper

Quartz-bearing alkali feldspar syenite/porphyritic igneous rock, commonly marketed as Dalmatian jasper

Polished kambaba jasper

Orbicular stromatolitic jasper; microcrystalline quartz (SiO₂) with chlorite/amphibole-rich inclusions

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)

Chert

Microcrystalline Quartz (SiO2)

Chert pebble

Microcrystalline silica (SiO2)

Dyed tumbled stone, likely chalcedony or quartz

Microcrystalline quartz (SiO₂), probably dyed magenta