Mineral In A Matrix (Likely Quartz Or Feldspar)

Granite (probable)

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

Granitic Pegmatite (Muscovite and Quartz)

Pegmatite (KAl2(AlSi3O10)(OH)2 / SiO2)

Weathered conglomeratic rock, likely iron-stained sandstone

Probable ferruginous, clast-bearing sandstone; exact identification requires examination of a fresh surface

Quartz-bearing Pegmatite with Metallic Sulfides

Pegmatite / Quartz-Feldspar Matrix with Pyrite and Mica

Quartz-bearing pegmatitic rock, likely quartz–feldspar–mica specimen

Granitic pegmatite; primarily quartz (SiO₂), feldspar, and mica, with possible iron-oxide staining

Basalt with Quartz/Feldspar Vein

Amygdaloidal Basalt with Plutonic intrusion (SiO2/KAlSi3O8)

Graphic Granite

Graphic Granite (Granite Pegmatite)

Greywacke (likely)

Greywacke (a type of sandstone)

Quartz-rich feldspathic rock, likely granite or granitic gneiss

Granite/granitic gneiss; chiefly quartz (SiO₂), feldspar, and minor mica

Porphyry (Basaltic / Andesitic Porphyry)

Porphyritic Basalt / Porphyritic Andesite

Biotite-rich granite or gneiss fragment

Dark mica-bearing granitoid; likely quartz–feldspar–biotite rock

Granite with Epidote

Granite, containing quartz, feldspar, and epidote

Mica-rich pegmatite (likely muscovite-bearing)

Granitic pegmatite composed mainly of quartz, feldspar, and mica; mica is likely muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Vein-bearing sandstone or quartzite cobble

Quartz-rich sandstone with white quartz veins; possibly metamorphosed to quartzite

Rose Quartz with Schist Matrix

Silicon Dioxide (SiO2) with Mica-Schist

Black Tourmaline in Quartz Matrix

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4)

Sandstone

Sandstone (Siliciclastic Sedimentary Rock)

Mica-rich granite (likely weathered pegmatitic granite)

Granite, composed mainly of quartz (SiO₂), feldspar, and mica (often muscovite and/or biotite)

Raw greenish mica-rich mineral specimen

Likely muscovite mica with quartz or feldspar inclusions; exact identification requires testing

Smoky Quartz and Biotite Schist

Quartz-Biotite Schist (SiO2 + K(Mg,Fe)3AlSi3O10(F,OH)2)

Porphyritic volcanic rock, likely porphyritic andesite

Porphyritic andesite; predominantly plagioclase feldspar phenocrysts in a fine volcanic groundmass, possibly with pyroxene or amphibole

Polished amethyst and dark polished stone

Amethyst: purple quartz, SiO₂; dark specimen: likely black tourmaline, obsidian, or dark agate (uncertain from image)

Amethyst (purple quartz), likely with quartz matrix

Quartz, silicon dioxide (SiO₂), purple variety colored mainly by iron-related impurities and irradiation

Orbicular jasper (likely ocean jasper)

Silica-rich chalcedony/quartz with hematite- or feldspar-rich orbicules; commonly marketed as Ocean Jasper

Quartz-rich granite or granitic pegmatite cobble

Granite/pegmatite, chiefly quartz (SiO₂) with feldspar and minor iron-oxide staining

Porphyritic Basalt

Porphyritic Basalt (containing Plagioclase phenocrysts)

Polished granite

Granite; chiefly quartz, feldspar, and mica/amphibole

Milky quartz with dark host-rock inclusions

Quartz (SiO₂), likely in a granitic or metamorphic matrix

Pegmatitic granite (quartz–feldspar–mica rock)

Granitic pegmatite; primarily quartz (SiO₂), K-feldspar/plagioclase, and biotite or muscovite mica

Quartz-rich rock fragment

Unidentified quartz–feldspar-rich rock; exact lithology cannot be determined from the image

Unakite / Feldspar Veined Metamorphic Pebble

Metamorphic Rock with K-Feldspar, Epidote, and Quartz

Weathered gray stone, possibly basalt or granitic rock

Indeterminate fine- to medium-grained silicate rock; possible basalt, diabase, or weathered granite

Porphyritic Rhyolite

Rhyolite (Porphyry)

Iron-stained quartz-bearing rock, possibly weathered granite or pegmatite

Quartz-rich felsic rock with iron oxyhydroxides (goethite/limonite); exact classification requires testing

Pegmatitic granite (likely garnet-bearing)

Coarse-grained granite/pegmatite; quartz + feldspar ± biotite/hornblende and almandine garnet

Weathered basalt or andesitic volcanic rock

Porphyritic basalt–andesite; likely plagioclase and pyroxene with iron-oxide alteration

Lepidolite with Tourmaline in Quartz Matrix

K(Li,Al)3(Si,Al)4O10(F,OH)2 (Lepidolite) / SiO2 (Quartz)

Dalmatian Stone

Peralkaline Feldsphathic Igneous Rock

Quartz-rich pegmatitic rock, possibly altered granite

Quartz–feldspar pegmatite; probable composition of quartz (SiO₂), feldspar, and mica/secondary alteration minerals

K2 Jasper (Beads)

Granodiorite with Azurite and Malachite

Mixed gravelly conglomeratic road aggregate

Polymictic clast-supported conglomerate or fill; composition varies, commonly quartz, feldspar, basalt, and weathered rock fragments

Quartz-rich breccia or iron-stained quartz

Microcrystalline to crystalline quartz (SiO₂), with probable iron-oxide staining and minor host-rock fragments