Mineral In A Matrix (Likely Quartz Or Feldspar)

Biotite Mica

K(Mg,Fe)3AlSi3O10(OH)2

Banded gneiss pebble

Gneiss, likely quartz–feldspar–mica gneiss

Weathered iron-rich sandstone or conglomeratic sedimentary cobble

Ferruginous sandstone, possibly polymictic conglomerate

Porphyritic Rhyolite

Porphyritic Rhyolite (Extrusive Igneous Rock)

Granite or Pegmatite in host rock

Granitoid / Felsic Intrusive Rock

Quartz-bearing conglomeratic rock with orange feldspar/calcite inclusion

Probably porphyritic granite or granitic pegmatite; exact identification requires a thin section or tests

Granitic Quartz with Feldspar

Granite (composed primarily of SiO2 and KAlSi3O8)

White quartz in dark matrix (likely quartz-bearing breccia or polished composite specimen)

Quartz, SiO₂, in an unidentified dark silicate matrix

Polished orbicular/porphyritic granite or breccia

Likely potassium-feldspar–quartz granite with amphibole/biotite and epidote; exact variety uncertain from the image

Quartz-rich pegmatite or quartz vein rock

Mostly quartz (SiO₂), with probable feldspar and iron-oxide staining

Sandstone (likely Quartz Sandstone)

Arenite (SiO2 based)

Granite Pebble

Granite (Phaneritic Igneous Rock)

Tourmaline-bearing pegmatite

Quartz–feldspar pegmatite with black schorl tourmaline; minor mica likely present

Granitic Quartz (with Feldspar inclusions)

Quartz (SiO2) with Potassium Feldspar (KAlSi3O8)

Granite

Felsic intrusive igneous rock (Granite)

Basalt with Quartz/Calcite Vein

Basalt (Mafic Volcanic Rock with secondary mineralization)

Epidosite with Quartz (Unakite-variant or Jasper)

Epidotized Metasomatite

Granitic Gneiss

Gneiss (containing Potassium Feldspar and Quartz)

Pegmatite (Granitic) with Tourmaline

Granitic Pegmatite (containing Schorl and Quartz)

Granite with Tourmaline or Biotite

Phaneritic Igneous Rock (Granoid)

Basalt with Quartz/Feldspar Inclusions

Amygdaloidal or Porphyritic Mafic Volcanic Rock with Siliceous Veining

Granite or Porphyritic Igneous Rock (weathered)

Granitoid

Black-and-white gneiss

Gneiss, chiefly quartz–feldspar with dark biotite/amphibole bands

Milky quartz (rough quartz specimen)

Quartz, silicon dioxide (SiO₂)

Weathered gray sandstone or siltstone

Clastic siliciclastic rock, primarily quartz and feldspar grains cemented by silica or carbonate

Pink-and-white quartz-rich rock, likely rose quartz matrix

Quartz (SiO₂), possibly intergrown with feldspar or chalcedony

Likely porphyritic igneous rock (possibly granite or rhyolite)

Quartz–feldspar–mica aggregate; exact identification requires a fresh surface and tests

Biotite-bearing granite or granitic gneiss

Quartz–feldspar granite with biotite mica; possibly weakly foliated gneiss

Chrysocolla-bearing rock (likely chrysocolla in quartz/limonite matrix)

Chrysocolla, hydrated copper aluminosilicate: (Cu,Al)₂H₂Si₂O₅(OH)₄·nH₂O

Milky quartz with iron-oxide staining and dark matrix

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

Weathered Sandstone or Siltstone

Sedimentary Rock

Likely quartz-rich rock fragment

Quartz (SiO₂), possibly in a feldspar-bearing granite or pegmatite matrix

Likely weathered quartz-rich stone

Indeterminate; possibly quartz-bearing granite or milky quartz

Weathered quartz-bearing rock, possibly gneiss or quartzite

Indeterminate; likely quartz-rich metamorphic rock containing quartz and feldspar

Smoky quartz-bearing pegmatitic rock

Quartz, SiO₂, likely with feldspar and mica inclusions

Granite with Quartz inclusion

Granite (Mainly SiO2, KAlSi3O8, NaAlSi3O8)

Amazonite

Triklinic Potassium Feldspar (KAlSi3O8)

Porphyritic Basalt

Amygdaloidal Porphyritic Basalt

Graphic Granite (or Pegmatite)

Graphic Granite

Prase Quartz on Feldspar

Quartz (Silicon Dioxide, SiO2) with Hedenbergite inclusions on Potassium Feldspar (KAlSi3O8)

Unakite (likely)

Epidote–pink feldspar–quartz rock; commonly termed unakite

Banded gneiss (likely amphibolite-bearing gneiss)

Gneiss; quartz–feldspar–mica/amphibole aggregate