Mineral In A Matrix (Likely Quartz Or Feldspar)

Porphyritic rhyolite

Rhyolite, a silica-rich volcanic rock; likely quartz–feldspar porphyry

Basalt with Feldspar phenocrysts

Aphanitic to Porphyritic Mafic Volcanic Rock

Black-and-white granite

Granite, chiefly quartz–feldspar–mica aggregate

Siltstone with Quartz Vein

Siltstone (composed of Quartz and Clay minerals) with a hydrothermal Quartz vein (SiO2)

Graphic Granite

Graphic Granite (variety of Pegmatite)

Sandstone (with vugs)

Arenite / Sedimentary Sandstone

Granite (likely)

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

Weathered, iron-stained quartz-rich pebble (uncertain identification)

Microcrystalline quartz, SiO₂, with iron-oxide/hydroxide staining and dark matrix inclusions

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Likely pegmatite with quartz and mica

Granitic pegmatite, chiefly quartz (SiO₂), feldspar, and mica

Graphic Granite

Graphic Granite (variety of Pegmatite)

Pegmatite with Schorl (Black Tourmaline) and Mica

Pegmatite (complex association of NaAlSi3O8, NaFe3Al6(BO3)3Si6O18(OH)4, and KAl2(AlSi3O10)(OH,F)2)

Polymictic conglomerate

Clast-supported conglomerate, typically quartz- and feldspar-rich in a dark matrix

Quartz Veined Rock (Likely Graywacke or Quartzite)

Silicon Dioxide (SiO2) veins in Metasedimentary matrix

Likely rough feldspar-bearing granite or pegmatite fragment

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

Sandstone

Sandstone (Quartzose/Feldspathic Sandstone)

Porphyritic basalt or andesite

Porphyritic volcanic rock; typically plagioclase phenocrysts in a fine mafic/intermediate groundmass

Quartz Geode / Druzy Quartz

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, likely granite or pegmatite fragment

Granite/pegmatitic granitoid; chiefly quartz (SiO₂), feldspar, and minor mica or iron oxides

Orbicular granite (likely orbicular diorite)

Orbicular granitoid; chiefly quartz, feldspar, biotite/hornblende, with orbicules of concentric feldspathic minerals

Que Sera Stone (Llanite with Feldspar and Quartz)

Rhyolite with blue quartz and pink orthoclase (Llanite-type quartz porphyry)

Metamorphic rock outcrop, likely schist or gneiss

Foliated metamorphic rock; exact mineral assemblage cannot be determined from the image

Banded gneiss pebble

Gneiss, a foliated metamorphic rock, likely quartz–feldspar–mica gneiss

Weathered pegmatitic granite

Granite/pegmatite, chiefly quartz (SiO₂), feldspar, and mica

Quartz in Limonite-rich Matrix

Silicon Dioxide (SiO2) with Goethite/Limonite FeO(OH)·nH2O

Milky quartz

Quartz (silicon dioxide, SiO₂)

Small brown mineral fragment (undetermined)

Unidentified; image detail is insufficient for a reliable species identification

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Sandstone (Quartzose / Feldspathic Sandstone)

Arenite (SiO2 principal matrix)

Mixed Mineral Collection (with Quartz, Beryl, and host rock)

Silicon Dioxide (Quartz), Be3Al2Si6O18 (Beryl), and associated Schist/Pegmatite

Orbicular rhyolite (likely)

Rhyolite, a silica-rich volcanic rock; commonly quartz, alkali feldspar, plagioclase, and iron-rich alteration minerals

Druzy amethyst (likely)

Quartz, SiO₂, with purple coloration from trace iron and irradiation

Chrysocolla-bearing quartz (likely chrysocolla in quartz)

Chrysocolla, hydrated copper aluminosilicate: approximately (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O, intergrown with quartz (SiO₂)

Weathered quartz-rich rock, possibly granite or quartzite

Indeterminate quartz–feldspar aggregate; likely weathered granite (quartz, feldspar, minor iron oxides)

Quartz–feldspar pegmatite with garnet

Granitic pegmatite; chiefly quartz (SiO₂), feldspar, mica, and reddish-brown almandine garnet

Weathered conglomerate pebble

Polymictic conglomerate, likely quartz- and feldspar-rich clasts in a cemented matrix

Likely weathered granite

Granite, chiefly quartz, feldspar, and mica

Small cream-colored tumbled stone, possibly quartz or feldspar

Undetermined; appearance alone is insufficient to identify the mineral

Pink-and-gray granite or granitic gneiss

Quartz–feldspar granite; possibly foliated granitic gneiss

Quartz-rich granitic fragment

Granite or granitic pegmatite; chiefly quartz (SiO₂), feldspar, and minor mica

Amethyst cluster

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

K2 granite (K2 stone)

Granite composed mainly of orthoclase and plagioclase feldspar, quartz, and biotite or hornblende