Mineral In A Matrix (Likely Quartz Or Feldspar)

Schist with sulfide mineralization

Mica schist, likely containing pyrite and/or chalcopyrite; quartz-rich matrix

Unakite-like granite with a white feldspar inclusion

Granite, chiefly quartz–feldspar–biotite; pale inclusion likely albite/orthoclase feldspar

Tumbled K2 stone (granite with blue azurite)

K2 granite, chiefly quartz–alkali feldspar–biotite with azurite inclusions

Pegmatite with Black Tourmaline

Granitic Pegmatite with Schorl (NaFe2+3Al6(Si6O18)(BO3)3(OH)3OH)

Sandstone (Pebble)

Arenite / Clastic Sedimentary Rock

Quartz (in matrix)

Quartz (SiO₂)

Conglomeratic gravel / polymictic breccia

Polymictic rudite, likely anthropogenic or beach/stream gravel; composition varies

Osumilite in Granite Matrix

(K,Na)(Fe,Mg)2(Al,Fe)3(Si,Al)12O30

Pyrite-bearing schist or quartzite

Micaceous quartz-rich metamorphic rock with pyrite (FeS₂)

Asphalt aggregate

Human-made bituminous asphalt containing crushed silicate rock aggregate

Black tourmaline-bearing pegmatite or schorl-rich metamorphic rock

Schorl tourmaline, NaFe3Al6(BO3)3Si6O18(OH)4, with quartz/feldspar and iron-oxide matrix

Tumbled lepidolite-rich pegmatite (probable)

Lepidolite, K(Li,Al)3(Si,Al)4O10(F,OH)2, in a granitic pegmatite matrix

Porphyritic Rhyolite

Porphyritic Rhyolite (Felsic volcanic rock)

Iron-stained quartz cluster

Quartz (SiO₂), likely with limonite/goethite staining and possible feldspar matrix

Exposed aggregate concrete (stone-chip surface)

Portland-cement concrete containing natural aggregate; not a natural rock

Muscovite Mica (likely on Quartz/Feldspar)

Muscovite - KAl2(AlSi3O10)(OH)2

Granite Pebble

Granite (Phaneritic intrusive igneous rock comprising Quartz, Feldspar, and Mica)

Weathered quartz-rich rock, likely arkose or quartzite

Quartz-dominant siliciclastic rock; probable arkose (quartz + feldspar), possibly weakly metamorphosed quartzite

Quartz-rich pegmatite fragment

Granite-family pegmatite; chiefly quartz (SiO₂), feldspar, and black mica (biotite)

Quartz (in a rock matrix)

Quartz (SiO2)

Polished brecciated jasper

Jasper (microcrystalline quartz, SiO₂), likely brecciated and iron-oxide stained

Conglomerate

Clast-supported polymictic conglomerate; rounded quartz and other rock fragments in a dark matrix

Pink calcite (likely manganocalcite)

Calcite, CaCO₃; pink color commonly caused by manganese impurities

Tourmaline-bearing pegmatite, likely schorl

Black tourmaline (schorl), NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄, in quartz-rich pegmatite

Pegmatite with quartz and feldspar

Granitic pegmatite, chiefly quartz (SiO₂) and feldspar (likely potassium feldspar or plagioclase)

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with feldspar, clay minerals, and iron oxides

Quartz vein in weathered host rock

Milky quartz (SiO₂), likely in a granitic or metamorphic matrix

Raw black tourmaline (likely schorl)

Schorl, sodium–iron tourmaline; approximately NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Quartz Vein in Sedimentary Rock

Silicon Dioxide (SiO2) with host Chert or Limestone

Likely weathered granite or granitic pegmatite fragment

Granite; chiefly quartz, feldspar, and minor mica (exact identification uncertain from the image)

Likely sandstone

Quartz-rich sandstone, probably arkosic or lithic sandstone

Quartz-rich pegmatite with amethyst and iron-oxide staining

Quartz (SiO₂) with purple amethyst variety, likely feldspar and hematite/goethite inclusions

Milky quartz vein fragment

Quartz (silicon dioxide, SiO₂), massive/microcrystalline variety

Amazonite in Pegmatite Matrix with Smoky Quartz

K(AlSi3O8) - Microcline (var. Amazonite) with SiO2 (Quartz)

Uncertain polymict breccia or altered volcanic rock

Likely hydrothermally altered volcanic breccia; exact mineral identification requires testing

Tourmaline-bearing pegmatite

Quartz–feldspar pegmatite with black schorl tourmaline (NaFe3Al6(BO3)3Si6O18(OH)4)

Basalt (with Plagioclase Phenocrysts)

Porphyritic Basalt

Weathered micaceous metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite; commonly quartz, muscovite/biotite, and feldspar

Weathered quartz-rich river cobble

Likely granitic or quartzitic rock; exact identification is uncertain from the photograph

Quartz-rich conglomeratic rock (likely granitic breccia or conglomerate)

Uncertain; quartz–feldspar rock in a fine-grained matrix, possibly weathered granite or polymictic conglomerate

Tourmaline-bearing pegmatite

Granitic pegmatite composed mainly of quartz, feldspar, mica, and schorl/elbaite tourmaline

Glacial Granite with Epidote

Granite featuring Epidote (Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH))