Metamorphic Or Sedimentary (With Staining)

Tumbled milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Banded sandstone or quartzite fragment

Quartz-rich sandstone; possibly weakly metamorphosed quartzite

Weathered foliated metamorphic rock, likely schist or gneiss

Micaceous quartz–feldspar metamorphic rock; exact mineralogy requires testing

Quartzite

Quartzite (containing SiO2)

Jasper pebble

Silicon Dioxide (SiO2) with iron oxide impurities

Mica Schist with Iron Staining

Muscovite/Biotite Schist

Gneiss

Gneiss (Foliated Metamorphic Rock)

River Stone (Granitic Gneiss)

Foliated Granitic Gneiss

Veined Limestone (or Quartz-Veined Slate/Shale)

Metamorphosed Sedimentary Rock with Calcite/Quartz Veins

Quartzite

Quartzite (consisting primarily of SiO2)

Banded quartzite pebble

Quartzite, predominantly quartz (SiO₂) with iron-oxide staining

Small quartz-rich pebble or rock fragment

Quartz (silicon dioxide, SiO₂), possibly with iron-oxide staining or host-rock inclusions

Rounded quartz-rich pebble, likely quartzite or quartz sandstone

Quartzite (mostly SiO₂), possibly ferruginous quartz sandstone

Pink Quartzite

Quartzite (SiO2 with iron oxide inclusions)

Quartzite (or Iron-Stained Quartz Pebble)

Silicon Dioxide (SiO2) with Ferric Oxide inclusions

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Quartz-bearing metamorphic rock, likely schist or quartzite

Quartz (SiO₂) in a mica-rich metamorphic matrix

Weathered quartz-rich pebble, likely sandstone or quartzite

Quartzite (SiO₂), possibly ferruginous sandstone

Ferruginous Quartz (Iron-stained Quartzite)

Silicon Dioxide (SiO2) with iron oxide inclusions

Iron-stained quartzite or quartz-rich metamorphic rock

Quartzite, predominantly SiO₂, with iron-oxide coatings (goethite/hematite)

Weathered quartz-rich rock, possibly quartzite

Quartzite (mostly SiO₂), though the photograph is insufficient for confident identification

Mica-rich metamorphic rock, likely schist

Muscovite–biotite schist, possibly with quartz and feldspar

Quartz (Milky/Chalcedony variety)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz-rich hydrothermal vein rock, possibly quartzite

Mostly SiO₂ (quartz), with probable iron oxides and minor sulfides

Quartz Vein in Schist

Quartz (SiO2) in Pelitic Schist

Polished jasper pendant

Jasper, an opaque microcrystalline variety of quartz (SiO₂), commonly colored by iron oxides

Milky quartz (likely quartz-rich rock)

Quartz, silicon dioxide (SiO₂)

Vesicular basalt with secondary mineralization

Mafic volcanic rock, chiefly plagioclase and pyroxene, with iron oxides and likely zeolite/calcite infillings

Agate

Chalcedony (SiO2) with impurities

Quartzite

Quartzite (SiO2)

Rounded iron-rich pebble

Likely ironstone or ferruginous quartzite; exact identification requires testing

Quartz pebble

Silicon Dioxide (SiO2)

Rounded granitic gneiss cobble

Foliated quartz–feldspar–mica gneiss; likely granitoid-derived

Weathered quartz-rich pebble

Likely quartzite or silicified rock with iron-oxide staining; chiefly SiO₂

Milky quartz vein rock

Quartz, silicon dioxide (SiO₂), likely massive vein quartz with iron-oxide staining

Rounded sandstone or quartzite pebble

Indeterminate; likely quartz-rich sandstone (SiO₂-dominated)

Weathered quartz-rich pebble, possibly quartzite or chert

Quartz (SiO₂), possibly quartzite; exact identification is uncertain from the image

Quartzite River Stone

Quartzite (primarily SiO2)

Yellow Aventurine (Tumbled)

Silicon Dioxide (SiO2) with inclusions

Weathered iron-rich metamorphic rock, possibly schist or metabasalt

Provisional identification: chlorite–quartz–feldspar schist or altered basalt; exact mineralogy requires testing

Weathered sandstone or iron-stained quartzite

Quartz-rich sandstone; possibly weakly metamorphosed quartzite (SiO₂-dominant)