Mineral In A Matrix (Likely Quartz Or Feldspar)

Pink Granite

Phaneritic Felsic Igneous Rock (Granite)

Graphic Granite

Graphic Granite (Granitic Pegmatite), typically KAlSi3O8 (Feldspar) + SiO2 (Quartz)

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely in a limonite/goethite-rich matrix

Porphyritic Basalt (or Andesite) containing Augite

Porphyritic Mafic Volcanic Rock

Milky quartz vein fragment

Quartz, silicon dioxide (SiO₂), commonly with minor iron-oxide staining and possibly feldspar

Likely smoky quartz-bearing rock or quartz crystal

Quartz, silicon dioxide (SiO₂), possibly smoky quartz with iron- or irradiation-related coloration

Granitic Pegmatite with Tourmaline and Sphalerite

Pegmatite containing Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) and Sphalerite ((Zn,Fe)S)

Pink Granite

Phaneritic Felsic Igneous Rock

Polished pegmatitic granite (likely graphic granite)

Coarse-grained granitic rock composed chiefly of quartz, feldspar, and biotite/hornblende

Chrysocolla on Matrix

Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)

Tumbled granite or granitic gneiss pebble

Granite/granitic gneiss, chiefly quartz, feldspar, and dark biotite or amphibole

Sandstone (likely Arkosic)

Arenite (SiO2 with KAlSi3O8)

Sandstone (Greywacke/Lithic Sandstone)

Arenite (composed primarily of SiO2)

Granite-like granitic rock

Crystalline plutonic rock, primarily quartz, feldspar, and mica/amphibole

Vesicular volcanic rock, likely weathered scoria

Scoria (vesicular basaltic-andesitic volcanic rock), composition approximately plagioclase, pyroxene, and volcanic glass

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Banded metamorphic rock, likely mica schist or gneiss

Quartz–feldspar–mica schist/gneiss; exact identification requires a fresh surface and mineral tests

Banded metamorphic rock, likely gneiss

Biotite–quartz–feldspar gneiss, possibly migmatitic

Banded gneiss

Gneiss, commonly quartz–feldspar–mica gneiss

Polished pink granite pebble

Granite; primarily quartz, potassium feldspar, plagioclase, and minor biotite/hornblende

Porphyritic granite or granitic gneiss

Quartz–feldspar–mica granitoid; exact identification requires testing

Granitic Pegmatite

Granite Pegmatite (coarse-grained intrusive igneous rock)

Likely quartz-bearing rock or quartz crystal fragment

Quartz, silicon dioxide (SiO₂), possibly with iron-stained matrix

Andesite

Intermediate Volcanic Rock (Andesite)

Likely gneiss

Gneiss, composed chiefly of quartz, feldspar, and mica/amphibole

Garnetiferous Quartzite (Garnet Gneiss Pebble)

Garnet-bearing Quartzite or Quartz-Feldspar Gneiss

Coarse-grained Quartz with Feldspar inclusions

Crystalline Quartz (SiO2) with Orthoclase/Plagioclase Feldspar inclusions

Pegmatitic granite

Coarse-grained granite, chiefly quartz, feldspar, and mica; likely a granitic pegmatite

Graphic Granite

Pegmatitic Quartz-Feldspar Granite

Quartz geode / iron-stained quartz vein rock

Quartz (SiO₂), likely with iron oxides and minor feldspar or host-rock minerals

Weathered granite or granitic rock

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

Sandstone

Quartz Arenite / Clastic Sedimentary Rock

Brecciated jasper (likely ocean jasper or rhyolitic jasper)

Silica-rich volcanic breccia composed mainly of microcrystalline quartz/chalcedony (SiO₂), with iron-oxide staining and possible feldspar

Likely graphite-rich schist (graphitic schist)

Graphitic schist; chiefly quartz, mica, and graphite (carbon), with possible pyrite or feldspar

Porphyritic Basalt

Basalt (Porphyritic texture)

Basalt with Plagioclase Porphyry

Porphyritic Basalt

Fossilized Shark Tooth (Fragment) in Matrix

Elasmobranchii (subclass)

Beryl (var. Aquamarine/Blue Beryl) in Quartz Matrix

Beryllium Aluminum Silicate (Be3Al2Si6O18)

Biotite-bearing granite or gneiss

Felsic granitoid; chiefly quartz, feldspar, and biotite mica

Beryl (likely Emerald or Aquamarine in matrix)

Beryllium aluminum silicate (Be3Al2Si6O18)

Unidentified weathered rock fragments

Likely mixed quartz- and feldspar-bearing silicate material; exact identification requires testing

Sandstone

Arenite (SiO2 predominantly)