Not A Rock Or Mineral

Granite (likely weathered)

Granite, a quartz–feldspar–mica intrusive igneous rock

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2)

Amethyst

Amethyst (Silicon Dioxide - SiO2)

Agate Geode

Silicon Dioxide (Chalcedony/Quartz), SiO2

Granodiorite

Granodiorite (containing Quartz, Plagioclase Feldspar, Biotite, and Hornblende)

Pink granite pebble

Granite, a coarse-grained felsic intrusive igneous rock

Rounded river pebble, likely granite or granitic gneiss

Granite-dominated felsic silicate rock; typically quartz, feldspar, and mica

Dark green, fine-grained pebble (likely amphibolite or greenstone)

Likely amphibolite, composed mainly of hornblende and plagioclase; exact identification requires examination

Granite (Leucogranite)

Felsic Plutonic Rock (Granite)

Petrified Wood

Silicified Wood (SiO2)

Tumbled labradorite (probable)

Labradorite, a plagioclase feldspar; approximate formula (Ca,Na)(Al,Si)₄O₈

Quartz Geode (Druzy Quartz)

Silicon Dioxide (SiO2)

Granite-like felsic rock

Likely weathered granite or granitic gneiss; predominantly quartz, feldspar, and minor mica

Gravel

Unconsolidated aggregate of mixed rock and mineral fragments

Granite

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and mica

Unakite

Unakite, an epidote-altered granite composed mainly of epidote, pink orthoclase feldspar, and quartz

Labradorite

Labradorite, a plagioclase feldspar in the albite–anorthite series, approximately (Ca,Na)(Al,Si)₄O₈

Quartz pebble in a coarse mineral-rich rock

Quartz (SiO₂), possibly in a quartz-rich conglomerate or breccia

Amygdoidal Basalt

Extrusive mafic igneous rock with mineral amygdules

Conglomerate

Lithified, poorly sorted gravel and sand; exact mineral composition is not identifiable from the image

Grey River Stone (Gneiss/Schist mix)

Foliated Metamorphic Rock (variable mineral formula)

Weathered feldspar-rich pegmatite or granite outcrop

Quartz–feldspar granitoid, likely containing potassium feldspar (KAlSi₃O₈) and quartz (SiO₂)

Druzy Quartz Geode (with Chalcedony)

Silicon Dioxide (SiO2)

Weathered granite

Granite, a coarse-grained felsic intrusive igneous rock composed mainly of quartz, feldspar, and mica

Weathered granite

Granite, primarily quartz, alkali feldspar, plagioclase, and mica

Petrified Wood

Silicified Wood (SiO2)

Orbicular Gabbro

Orbicular Gabbro

Porphyry

Porphyritic Igneous Rock

Likely weathered granite or granitic gneiss fragment

Granite: quartz + feldspar + mica; possibly gneiss if foliation is confirmed

Banded gneiss

Foliated gneiss, likely quartz–feldspar–biotite or amphibole gneiss

Jasper and Quartz Breccia

Silicified Breccia / Microcrystalline Quartz

Ironstone (iron-oxide-rich rock)

Ferruginous sandstone or ironstone; likely composed chiefly of goethite and/or limonite, with quartz and clay

Gneiss

Quartz–feldspar–mica gneiss

Man-made earbud charging case (Not a rock or mineral)

Acrylonitrile Butadiene Styrene (ABS) Plastic with electronic components

Unidentifiable Specimen

Undetermined

Tumbled basalt (likely vesicular basalt)

Basalt; primarily plagioclase, clinopyroxene, and olivine, with iron oxides

Likely weathered iron-rich rock or mineral fragment

Indeterminate; possibly limonite/goethite-rich material with quartz or feldspar

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Petrified Wood

Silicified Wood (SiO2)

Uncertain fine-grained rock or mineral-bearing specimen

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

Likely weathered quartz-rich rock or mineral fragment

Indeterminate from image; possibly quartz-bearing pegmatite or iron-stained quartz

Unidentified dark reddish-brown rock or mineral specimen

Indeterminate from the blurred image; possibly iron-stained quartz, jasper, or a metallic sulfide-bearing rock