Mineraloid (Anthropogenic)

Iron-oxide-rich breccia or weathered ironstone

Hematite–goethite ironstone, likely brecciated and quartz-bearing

Rhyolite (possibly porphyritic and altered)

Volcanic felsic rock; primarily quartz, alkali feldspar, plagioclase, and volcanic glass, with iron-oxide alteration

Weathered iron-rich sandstone or ironstone cobble

Ferruginous sandstone/ironstone, chiefly quartz (SiO₂) cemented or stained by iron oxides and hydroxides

Dark mafic rock, likely basalt

Basalt; primarily plagioclase feldspar and pyroxene, commonly with olivine and iron oxides

Malachite-bearing copper ore

Malachite (Cu₂CO₃(OH)₂), likely mixed with chrysocolla, limonite, or native copper minerals

Polished orbicular jasper (likely kambaba or ocean jasper)

Silicified microcrystalline quartz/chalcedony with iron-rich inclusions; mainly SiO₂

Metallic sulfide-bearing metamorphic rock

Likely graphitic schist or sulfide-rich schist, with possible pyrite/arsenopyrite and mica

Flint or chert fragment

Microcrystalline quartz (SiO₂), commonly termed chert or flint

Weathered iron-rich rock, likely magnetite-bearing basalt or ironstone

Basalt/ironstone mixture dominated by iron oxides, chiefly magnetite (Fe3O4) and hematite (Fe2O3)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, possibly with mica or feldspar

Fossilized shell, likely brachiopod or bivalve

Indeterminate fossil shell; possible Spiriferida brachiopod or thick-shelled bivalve

Tumbled azurite–malachite or blue jasper (tentative)

Likely azurite-bearing copper mineral aggregate; composition commonly Cu₃(CO₃)₂(OH)₂ with associated malachite Cu₂CO₃(OH)₂

Raw green calcite (likely)

Calcite, calcium carbonate (CaCO₃)

Polished septarian nodule

Septarian concretion, commonly calcite/aragonite with brown iron-oxide or siderite veins in a clay-rich matrix

Sandstone

Clastic sedimentary rock (primarily SiO2)

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous quartz–feldspar metamorphic rock; exact mineralogy requires testing

Banded slate or phyllite

Fine-grained foliated metasedimentary rock; likely slate with light-colored quartz veins

Fossil ammonite

Ammonoidea; likely a chambered ammonite mold/cast

Weathered volcanic rock fragment

Indeterminate fine-grained mafic-to-intermediate igneous rock; possibly andesite or basalt

Weathered sandstone pebble

Quartz-rich sandstone, likely iron-oxide-stained (SiO₂-dominant)

Rounded river pebble, likely quartz-rich sandstone or weathered quartzite

Indeterminate; probable quartz (SiO₂)-rich clastic rock

Greenstone pebble

Likely chlorite- or epidote-bearing metamafic rock (metabasalt/greenschist)

Probable weathered basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase ± pyroxene, amphibole, and iron oxides

Granite

Felsic intrusive igneous rock

Weathered porphyritic volcanic rock

Likely andesite or dacite, with feldspar phenocrysts in a fine-grained groundmass

Sandstone (Quartzose Sandstone)

Arenite (primarily SiO2 with minor Fe2O3)

Unidentified rounded mineral/rock fragment

Indeterminate; likely a weathered quartz-rich stone or iron-stained granite fragment

Gneiss

Gneiss

Unidentified gray weathered rock

Possibly weathered granite or granitic gneiss; exact identification requires a fresh surface and tests

Granite

Granite (Felsic Plutonic Rock)

Quartzite

Metamorphosed Quartz Sandstone (SiO2)

Rounded iron-rich concretion or weathered lateritic pebble

Goethite/hematite-bearing ferruginous concretion; exact mineralogy requires testing

Concretion (likely iron-rich sandstone or claystone concretion)

Diagenetic carbonate/iron-oxide concretion; exact mineralogy requires testing

Desert Rose Fragment (Atypical) / Weathered Chert

Silicon Dioxide (SiO2) or Barium Sulfate (BaSO4) depending on exact mineralogy

Banded Gneiss

Gneiss (Metamorphic rock of variable mineralogy, often quartz-feldspar base)

Schist

Schist (various mineralogical compositions including mica, chlorite, talc, etc.)

Serpentine-rich greenstone (probable serpentine/soapstone fragment)

Serpentine-group minerals, chiefly antigorite/lizardite; possibly minor talc, chlorite, and carbonate

Tumbled green aventurine (likely)

Quartzite dominated by quartz (SiO₂), with green fuchsite mica inclusions

Polished labradorite

Labradorite, calcium-rich plagioclase feldspar; approximately (Ca,Na)(Al,Si)₄O₈

Polished serpentinite pebble

Serpentinite; primarily serpentine-group minerals (Mg3Si2O5(OH)4), with possible magnetite and talc

Polished pink-and-green feldspar-bearing rock, likely unakite or aventurine granite

Unakite-like epidote–feldspar–quartz aggregate; composition commonly K-feldspar + quartz + epidote

Quartz-bearing dark mineral specimen

Quartz (SiO₂) on a dark host rock, possibly basalt or sulfide-rich ore