Mineral In A Matrix (Likely Quartz Or Feldspar)

Granite Pebble

Granite (Phaneritic Igneous Rock)

Rose quartz–bearing pegmatite (probable)

Quartz (SiO₂) in a granitic pegmatite matrix, possibly with feldspar

Polished gabbro or basalt with quartz/calcite veining

Mafic igneous rock; chiefly plagioclase and pyroxene, with light veins of quartz or calcite

Porphyritic Igneous Rock / Rhyolite Porphyry

Porphyritic volcanic rock

Pegmatitic granite (likely feldspar–quartz–mica rock)

Granitic pegmatite; chiefly K-feldspar and quartz, with mica and iron-oxide staining

Tumbled-looking granite pebble

Granite, chiefly quartz–feldspar with biotite/amphibole

Granitic Pegmatite with Schorl

Granitic Pegmatite (Schorl: NaFe3Al6(Si6O18)(BO3)3(OH)3OH)

Conglomeratic concrete or asphalt aggregate surface with dark bituminous chunks

Polymictic gravel aggregate; dark pieces likely bitumen/asphalt, not a natural rock

Quartz-rich rock fragment, likely milky quartz

Quartz (silicon dioxide, SiO₂), possibly an iron-stained quartz vein fragment

Vein-bearing metamorphic rock, likely gneiss or schist

Quartz-feldspar–mica metamorphic rock; exact identification requires testing

Orbicular jasper (likely ocean jasper)

Silica-rich microcrystalline quartz/chalcedony with iron-oxide and feldspar inclusions; commonly marketed as Ocean Jasper

Smoky Quartz in Matrix (Pegmatite)

Silicon Dioxide (SiO2) with Potassium Feldspar and Biotite mica

Red Granite

Phaneritic Felsic Igneous Rock (Quartz, Alkali Feldspar, Plagioclase)

Unakite-like granite with a white feldspar inclusion

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

Graphic Granite

Graphic Granite (Pegmatite)

Gabbro or Diorite with Quartz/Epidote Vein

Intrusive Igneous Rock (Plutonic)

Exposed aggregate concrete (stone-chip surface)

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

Smoky Quartz on Feldspar (Granite Pegmatite)

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (KAlSi3O8)

Pyrite in Matrix (likely Quartz or Schist matrix)

Iron Sulfide (FeS2)

Amazonite

Microcline Feldspar (KAlSi3O8)

Porphyritic volcanic rock (likely rhyolite or andesite)

Porphyritic rhyolite–andesite; fine volcanic groundmass with feldspar and mafic phenocrysts

Vesicular basalt (likely amygdaloidal basalt)

Basalt, a mafic volcanic rock composed mainly of plagioclase feldspar, clinopyroxene, and commonly olivine; vesicles are partly mineral-filled amygdules.

Pegmatitic mica-quartz-feldspar specimen

Granitic pegmatite, chiefly quartz (SiO₂), feldspar, and muscovite/biotite mica

Pegmatite with quartz, feldspar, mica, and tourmaline

Granitic pegmatite; chiefly quartz (SiO₂), feldspar, muscovite, and black schorl tourmaline (NaFe₃Al₆(BO₃)₃Si₆O₁₈(OH)₄)

Basalt Porphyry

Porphyritic Basalt

Porphyritic basalt (likely amygdaloidal basalt)

Basalt, a mafic volcanic rock; composition typically plagioclase + pyroxene, with possible olivine and vesicle-filling minerals

Quartz–feldspar pegmatite specimen

Granitic pegmatite, chiefly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), and mica-group minerals

Quartz with Feldspar and Matrix

Silicon Dioxide (SiO2) with Potassium/Plagioclase Feldspar

Granite Cobble

Felsic intrusive igneous rock

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous schist/gneiss; composition likely quartz, feldspar, mica, and altered mafic minerals

Raw black tourmaline (likely schorl)

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

Milky quartz vein fragment

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

Weathered feldspathic rock, likely granite or granitic pegmatite

Quartz–feldspar–mica aggregate; exact species indeterminate from the image

Amazonite in Pegmatite Matrix with Smoky Quartz

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

Mixed polished rock/mineral specimens

Indeterminate from image; likely quartz-bearing material with iron-oxide staining and possibly mica-rich schist

Quartz-rich pegmatite fragment

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

Black tourmaline-bearing pegmatite or schorl-rich metamorphic rock

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

Osumilite in Granite Matrix

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

Quartz vein rock with iron-stained matrix

Quartz (SiO₂), likely with limonite/goethite and minor feldspar or mica

Quartz (in matrix)

Quartz (SiO₂)

Muscovite Mica (likely on Quartz/Feldspar)

Muscovite - KAl2(AlSi3O10)(OH)2

Quartz (in a rock matrix)

Quartz (SiO2)