Industrial Byproduct (Anthropogenic Material)

Sandstone (Red/Brown)

Arenite (SiO2 dominated with iron oxides)

Red sandstone pebble

Quartz-rich sandstone, likely ferruginous arkose or litharenite

Dyed agate (likely dyed chalcedony)

Microcrystalline quartz, SiO₂ (chalcedony/agate)

Rough aquamarine (likely beryl)

Beryl, Be₃Al₂Si₆O₁₈; blue color from iron impurities

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Small pale mineral fragment

Unidentified; possibly quartz, calcite, or feldspar

Tumbled black-and-white stone, likely dendritic agate or jasper

Cryptocrystalline quartz (SiO₂), possibly chalcedony with manganese-oxide dendrites

Tiger’s eye

Chatoyant quartz (fibrous quartz pseudomorph after crocidolite), SiO₂

Tumbled citrine or iron-stained quartz

Quartz (SiO₂), likely iron-oxide-stained or natural citrine

Yellow Quartz Pebble

Silicon Dioxide (SiO2)

Schist

Mica Schist

Peridot (Olivine)

Olivine ((Mg, Fe)2SiO4)

Moissanite

Silicon Carbide (SiC)

Red Sandstone

Arenite (with Iron Oxide pigmentation)

Quartzite (Gold/Tan River Cobble)

Quartzite (composed primarily of crystalline SiO2)

Crushed Stone / Gravel

Aggregatus saxum (variable mineral composition)

Diamond (or Cubic Zirconia simulant)

Carbon (C) or Zirconium Dioxide (ZrO2)

Fossilized scallop shell fragment

Bivalve shell, composed primarily of calcite (CaCO₃)

Gravel or Crushed Stone

Fragmented Aggregate Stone

Green-tumbled stone, possibly epidote-bearing rock

Undetermined green silicate; possible epidote (Ca₂Al₂Fe³⁺(SiO₄)(Si₂O₇)O(OH)) in a rock matrix

Chert (Jasper variety)

Silicon Dioxide (SiO2)

Amazonite pendant

Amazonite, a green variety of microcline feldspar (KAlSi₃O₈)

Peridot in Matrix

Olivine ((Mg,Fe)2SiO4)

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Chalcedony nodule (possibly agate)

Microcrystalline quartz, SiO₂; potentially banded agate

Likely basalt pebble

Basalt, a fine-grained mafic volcanic rock; commonly composed of plagioclase, pyroxene, and sometimes olivine

Serpentine-rich serpentinite

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

Iron-rich meteorite candidate

Unclassified meteoritic iron–stone material; possible stony-iron meteorite or terrestrial ironstone

Iron-rich concretion or slag-like rock

Goethite–hematite limonite concretion, possibly iron slag

Green sea glass (likely slag glass or bottle glass)

Man-made soda-lime silicate glass; not a naturally occurring mineral

Black glassy fragment, likely obsidian or industrial glass

Volcanic glass (obsidian), chiefly amorphous SiO₂; identification uncertain from image

Polished blue banded stone, likely sodalite or blue apatite

Probable sodalite, Na₈(Al₆Si₆O₂₄)Cl₂; possibly blue apatite, Ca₅(PO₄)₃(F,Cl,OH)

Blue gemstone, likely tumbled sapphire or blue spinel

Corundum (Al₂O₃) if sapphire; alternatively spinel (MgAl₂O₄)

Diamond (or Diamond Simulant)

Carbon (C) if diamond, various if simulant

River Pebble (Gravel)

Clastic sedimentary rock (likely Siltstone or Mudstone pebble; SiO2 with various impurities)

Iron meteorite fragment

Fe-Ni meteorite, likely an iron meteorite or stony-iron fragment

Small weathered fossil or mineral fragment

Indeterminate; possibly fossilized shell, bone, or a pale carbonate mineral

Polished hematite bead (probable)

Hematite, Fe₂O₃

Limestone

Calcium Carbonate (CaCO3)

Quartz-rich pegmatitic rock with possible epidote or chlorite

Hydrothermal/pegmatitic quartz-bearing rock; identifiable minerals may include quartz (SiO₂), feldspar, and epidote/chlorite

Orange calcite

Calcite (CaCO₃), likely honey/orange calcite

Polished orbicular jasper (likely ocean jasper)

Orbicular jasper; chiefly microcrystalline quartz and chalcedony (SiO₂), with assorted mineral inclusions