Mineraloid (Anthropogenic)

Concrete Fragment

Hardened Portland Cement Composite

Uncertain dark gray-brown rock fragment

Indeterminate; possibly weathered chert, serpentine, or iron-stained quartzite

Fossilized oyster shell in limestone

Bivalvia fossil; chiefly calcite (CaCO₃)

Polished banded calcite/aragonite tower

Calcite (CaCO₃), possibly aragonite (CaCO₃)

Citrine

Silicon Dioxide (SiO2)

Greenstone (Metabalt)

Chlorite-actinolite schist (Greenstone)

Dalmatian jasper

Quartz-bearing, orbicular microcrystalline silica (commonly sold as “Dalmatian jasper”; often an altered porphyritic igneous rock)

River Pebbles (Stream-rounded rocks)

Fluvial Detritus (varied mineralogy)

Tumbled brown-and-black stone, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase, pyroxene, and possibly olivine or iron oxides

Geode with Quartz/Chalcedony

Silicon Dioxide (SiO2)

Polished bumblebee jasper (likely)

Calcite–sulfur-rich volcanic breccia, commonly sold as “bumblebee jasper”

Iron-rich metamorphic rock, likely specular hematite-bearing schist

Hematite–quartz–mica schist (tentative)

Small quartz-rich stone, possibly granite fragment

Indeterminate; likely quartz (SiO₂) with feldspar and/or mica

Petrified Wood

Silicified Wood (SiO2)

Iron-stained metamorphic rock, likely schist or quartzite

Quartz–mica–iron oxide rock; probable muscovite/biotite schist or ferruginous quartzite

Banded Gneiss (with Quartz Vein)

Gneiss (Metamorphic rock of varying mineralogy)

Tumbled lepidolite-rich pegmatite (probable)

Lepidolite, K(Li,Al)3(Si,Al)4O10(F,OH)2, in a granitic pegmatite matrix

Chert Arrowhead

Cryptocrystalline Quartz (SiO2)

Labradorite

(Ca, Na)(Al, Si)4O8 (Calcium Sodium Aluminum Silicate)

Sand Grain (Quartz)

Silicon Dioxide (SiO2)

Yellow-green aventurine or serpentine pendant

Most likely serpentine-group mineral (magnesium silicate), possibly quartz-rich aventurine

Weathered brown rock fragment, possibly iron-rich sandstone or altered basalt

Indeterminate; likely an iron-oxide–stained silicate rock

Optical Calcite

Calcium Carbonate (CaCO3)

Pistachio-green and dark mineral-bearing rock, possibly serpentine with dark inclusions

Undetermined; the image is insufficient for reliable species-level identification

Mixed River Pebbles (Jasper, Hematite, and Quartzites)

Silicon dioxide (Jasper/Quartz) and Iron oxide (Hematite)

Small rounded pebble

Indeterminate lithic clast; likely weathered quartzite, sandstone, or chert

Weathered greenish rock fragment

Indeterminate; possibly epidote- or chlorite-bearing altered silicate rock

Rounded river pebble (likely weathered granite or metamorphic rock)

Indeterminate; possible granitic or quartz-rich lithology

Chalcopyrite

Copper Iron Sulfide (CuFeS2)

Schist (likely Mica Schist)

Mica Schist

Dalmatian jasper (often sold as Dalmatian stone)

Quartz-bearing leucocratic alkali-feldspar–aegirine/arfvedsonite porphyritic rock; commercial “jasper” designation

Granite Cobble

Plutonic Granite

Graphite Schist

C (Carbonaceous Schist)

Possible green tourmaline (small rough crystal fragment)

Possibly elbaite, Na(Li₁.₅Al₁.₅)Al₆(Si₆O₁₈)(BO₃)₃(OH)₄; identification is uncertain from the blurry image

Small blue-green mineral or stone bead

Unidentified opaque blue-green mineral; the image is insufficient for reliable species identification

Small tumbled stone, likely quartz-rich pebble

Probably microcrystalline quartz (SiO₂), but the image is insufficient for a definitive identification

Small rounded stone or mineral fragment

Indeterminate; likely a common quartz- or feldspar-bearing silicate fragment

Raw ruby (likely corundum)

Corundum, Al₂O₃; red varieties are ruby

Cat's Eye Moonstone (Feldspar)

Orthoclase (KAlSi3O8) with Albite (NaAlSi3O8) inclusions

Bismuth crystal

Bismuth (Bi), commonly laboratory-grown

Polished amber

Fossilized tree resin (primarily organic polymerized diterpenes)

Hag Stone

Sandstone or Limestone with Solution Holes (Bioturbation/Erosion)