Not A Rock Or Mineral (Anthropogenic Material)

Clear Quartz

Silicon Dioxide (SiO2)

Red Sandstone

Arenite (Ferruginous Sandstone)

Shale (with Iron Staining)

Argillaceous mudstone / Shale

Bauxite

Bauxite (Mixture of Al(OH)3, AlO(OH), and Fe2O3)

Fossil Shell (Bivalve)

Class Bivalvia (fossilized)

Sandstone

Arenite (primarily SiO2)

Sandstone

Arenite (SiO2 primarily)

Sandstone

Arenite (SiO2 based)

Greenstone / altered mafic rock

Likely serpentinite or chlorite-rich metabasalt; exact identification requires testing

Speckled rounded stone, likely granite or granitic gneiss

Granite/granitic gneiss; primarily quartz (SiO₂), feldspar, and dark mica or amphibole

Weathered granite or granitic rock fragment

Granite; chiefly quartz, feldspar, and mica/amphibole

Coarse-grained Granite or Gneiss

Granitic intrusive rock

Iron-rich laterite or limonite/goethite concretion

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

Sandstone Pebble

Quartz Arenite / Sandstone

Greenish altered rock, possibly serpentinite or chlorite-rich schist

Tentative: serpentine-group minerals, chiefly antigorite/lizardite, or chlorite–actinolite assemblage

Unidentified dark rock fragment

Likely fine-grained mafic mineral aggregate; exact identification requires testing

Sandstone (with Iron concretions/staining)

Arenite (composed primarily of Quartz and Feldspar with Iron Oxide cement)

Sandstone (Glacial Cobble)

Arenite / Sedimentary Rock (primarily SiO2)

Likely basalt or another dark, coarse-grained igneous rock

Possibly olivine-bearing basalt (plagioclase, pyroxene, and possibly olivine); identification is uncertain from the photo

Sandstone with Liesegang Rings

Arenite with Iron Oxide Concretions

Milky Quartz

Silicon Dioxide (SiO2)

Sandstone Pebbles

Arenite (primarily SiO2 with mineral cement)

Jasper and Quartz Breccia

Silicified Breccia / Microcrystalline Quartz

Iron-rich stone, likely limonite/goethite-bearing rock

Limonite (hydrated iron oxides; chiefly goethite, FeO(OH), with possible hematite)

Small iron-stained quartz pebble

Quartz (SiO₂), with yellow-brown iron-oxide staining

Sandstone

Clastic Sedimentary Rock

Greenstone (Epidosite)

Epidosite (Metamorphosed Basalt/Diabase)

Unakite (polished/tumbled)

Unakite, an epidote-altered granite composed chiefly of epidote, pink potassium feldspar, and quartz

Quartz geode

Microcrystalline quartz (SiO₂), likely a small druzy quartz geode

Sandstone

Arenite (primarily Quartz and Feldspar composition)

Sandstone

Arenite (primarily Quartz-based)

Sandstone (likely Arkosic or Lithic Sandstone)

Arenite (SiO2 based with mineral inclusions)

Sandstone (Quartzose Sandstone)

Sandstone (SiO2 with various trace minerals)

Diamond (in Matrix)

Carbon (C)

Granite (likely weathered granitic rock)

Granite; chiefly quartz (SiO₂), feldspar, and mica

Biotite (Black Mica)

Biotite (K(Mg,Fe++)3AlSi3O10(OH,F)2)

Sandstone (Ferruginous)

Clastic Sedimentary Rock (Litharenite)

Small rounded stone or mineral fragment

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

Red Sandstone

Arenite (Iron-rich)

Polished operculum (“Shiva eye” shell)

Calcium-carbonate shell operculum, commonly from a turban snail (family Turbinidae); not a mineral specimen

Sandstone

Clastic sedimentary rock (Quartz arenite / Arkose)

Sandstone Pebble

Sedimentary quartz arenite