Igneous And Metamorphic Derivative (Weathered)

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Weathered quartz-rich rock, possibly quartzite or granitic fragment

Indeterminate; likely quartzite (mostly SiO₂) or quartz-bearing granitoid

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica, with possible iron-oxide weathering

Weathered pegmatitic granite or feldspar-rich metamorphic rock

Quartz–feldspar rock, likely granitic pegmatite; exact identification requires testing

Rounded quartz-rich pebble, possibly granite or granitic gneiss

Granite/granitic rock; chiefly quartz (SiO₂), feldspar, and minor mica or mafic minerals

Rounded pale pebble, likely quartz-rich stone

Indeterminate; possibly quartzite, quartz-bearing granite, or calcite-rich limestone

Rounded reddish-brown river pebble

Indeterminate weathered silicate rock, possibly granite, rhyolite, or iron-stained quartzite

Weathered gray metamorphic rock, likely schist or gneiss

Micaceous quartz-feldspar schist/gneiss; exact identification requires a fresh surface and testing

Weathered quartz-rich pebble

Quartz-bearing granitoid or quartzite; exact identification is uncertain from the image

Weathered metamorphic rock, likely schist or phyllite

Quartz–mica schist/phyllite (exact identification requires a fresh surface and tests)

Weathered gray metamorphic rock, likely gneiss or schist

Probable quartz–feldspar–mica gneiss/schist; exact identification requires a fresh surface and tests

Mica-rich rock, likely mica schist

Mica schist, composed chiefly of muscovite and/or biotite with quartz and feldspar

Rounded quartz-rich pebble

Likely granitoid-derived quartz–feldspar cobble; exact identification requires testing

Magnetite (Octahedral Crystal)

Magnetite (Fe3O4)

Rounded quartz-rich pebble, likely milky quartz

Quartz (SiO₂), possibly weathered quartzite or chalcedony

Probable weathered sulfide-bearing rock

Indeterminate; possibly pyrite- or chalcopyrite-bearing matrix

Small polished or naturally worn stone, possibly quartz-bearing rock

Indeterminate from the blurred image; likely quartz (SiO₂) or a pale feldspar-rich fragment

Weathered granitic gneiss

Granitic gneiss; quartz–feldspar–mica rock

Iron-stained quartz with possible feldspar

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

Mixed rock and mineral specimen collection

Varied silicate, carbonate, and oxide minerals; individual identification is not possible from this group photograph

Quartz (Field Stone)

Silicon Dioxide (SiO2)

Quartz (Yellow / Citrine Quartz Pebble)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

White quartz-rich pebble

Quartz (SiO₂), possibly milky quartz or quartzite

Quartz Pebble (with potential iron inclusions)

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Grey Agate

Silicon Dioxide (SiO2) - Variety of Chalcedony

Quartz vein fragment

Milky quartz (SiO₂), possibly with weathered host rock

Weathered coarse-grained igneous rock, likely diorite or gabbro

Diorite–gabbro compositional range; chiefly plagioclase feldspar, amphibole/pyroxene, and minor biotite or quartz

Likely weathered quartz-rich rock fragment

Uncertain; possibly quartz-bearing granitic or metamorphic material (SiO₂-dominant)

Granite Pebble on Flagstone

Granite (Felsic Plutonic Rock)

Weathered, quartz-rich metamorphic rock (likely schist or gneiss)

Quartz–feldspar–mica schist/gneiss, with surface lichens and iron-oxide staining

Possible hematite-rich ironstone or magnetite-bearing specimen

Likely hematite (Fe₂O₃), magnetite (Fe₃O₄), or an iron-rich slag-like geological specimen

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase ± pyroxene, possibly olivine)

Milky quartz (likely quartz fragment)

Quartz, silicon dioxide (SiO₂)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Quartz Pebble

Silicon Dioxide (SiO2)

Tumbled orange-brown quartz pebble

Likely iron-stained quartz or chalcedony (SiO₂)

Iron-stained quartz-rich cobble

Weathered granitic or quartz-feldspar rock; exact identification requires testing

Quartz with Iron Oxide Staining

Silicon Dioxide (SiO2)

Quartz (Milky or Clear variety)

Silicon Dioxide (SiO2)

Weathered metamorphic rock, likely gneiss or schist

Indeterminate foliated silicate rock; commonly quartz–feldspar–mica assemblage