Igneous And Metamorphic Derivative (Weathered)

Tumbled magnetite-bearing rock, likely basalt or gabbro

Magnetite (Fe₃O₄) in a mafic silicate matrix, probably basaltic or gabbroic

Milky quartz (rough quartz-rich rock)

Quartz, silicon dioxide (SiO₂); likely massive milky quartz, possibly quartzite

Dark metamorphic rock, likely hornfels or fine-grained basalt

Probable hornfels; commonly quartz–feldspar–mica with variable amphibole/pyroxene

Potassium feldspar

Orthoclase or microcline; KAlSi₃O₈

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Quartz pebble

Silicon dioxide (SiO2)

Mossy Rock

Mixed lithology rock with Bryophyta (moss)

Foliated metamorphic rock, likely marble or calc-schist

Calcite-rich marble/calc-schist; predominantly CaCO₃ (calcite), with possible mica and quartz

Coarse-grained metamorphic rock, likely gneiss or schist

Probable biotite-quartz-feldspar gneiss/schist; exact identification requires a fresh surface and tests

Citrine

Silicon dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Weathered rounded pebble

Likely altered granite or granitic gneiss fragment; exact identification is uncertain from the image

Milky quartz pebble

Quartz (silicon dioxide, SiO₂)

Weathered granitic gneiss

Quartz–feldspar–mica gneiss (compositionally granitic)

Banded gneiss

Gneiss, composed mainly of quartz, feldspar, and mica

Quartz-rich pale rock fragment

Likely milky quartz (SiO₂), possibly quartzite

Weathered quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly quartz (SiO₂), with minor iron-oxide staining and possible mica/clay minerals

Likely weathered granite or granitic gneiss fragment

Granite; chiefly quartz, feldspar, and mica

Milky Quartz with Iron Staining

Silicon Dioxide (SiO2)

Rounded, weathered quartz-rich pebble (likely milky quartz)

Quartz, SiO₂; exact identification is uncertain from the photograph

Weathered schist or gneiss cobble

Foliated silicate rock, likely mica schist or biotite gneiss

Milky quartz fragment

Quartz (SiO₂)

Quartz-rich pebble, possibly milky quartz with dark inclusions

Quartz (silicon dioxide, SiO₂), likely with iron-oxide or mica inclusions

Milky quartz

Quartz (silicon dioxide, SiO₂)

Dark gray metamorphic cobble, likely basalt or hornfels

Probable hornfels or fine-grained basalt; exact identification requires testing

Tumbled yellow-brown quartz (likely citrine or iron-stained quartz)

Quartz, silicon dioxide (SiO₂), commonly colored by iron-oxide inclusions

Tumbled reddish-brown basalt or andesite cobble

Fine-grained mafic to intermediate volcanic rock; commonly plagioclase, pyroxene, and magnetite, with iron-oxide staining

White quartz (likely milky quartz)

Quartz, silicon dioxide (SiO₂)

Quartz Pebble

Silicon Dioxide (SiO2)

Chalcopyrite

Chalcopyrite (CuFeS2)

Iron-stained quartz-rich rock, possibly gold-bearing quartz

Quartz (SiO₂) with iron-oxide staining; possible limonite/goethite matrix

Tourmaline-rich schist (likely black tourmaline)

Schist containing schorl, Fe-rich NaFe3Al6(BO3)3Si6O18(OH)4

Weathered granite or granitic gneiss

Granite; primarily quartz, feldspar, and mica (exact identification uncertain from the photo)

Quartz-bearing weathered rock

Massive to drusy quartz (SiO₂), possibly in a feldspathic or carbonate host

Clear Quartz

Silicon dioxide (SiO2)

Yellow quartz pebble

Quartz (SiO₂), likely iron-stained or naturally yellow quartz; exact variety cannot be determined visually

Milky quartz (iron-stained quartz)

Quartz, silicon dioxide (SiO₂)

Tumbled milky quartz

Quartz (silicon dioxide, SiO₂)

Mixed rock and mineral specimens

Multiple unidentified silicate rocks and minerals; likely quartz-bearing material, feldspar, mica, and iron-oxide-bearing stones

Milky quartz pebble

Quartz (SiO₂), cryptocrystalline to coarse microcrystalline variety

Quartz (Water-worn pebble)

Silicon Dioxide (SiO2)

Quartz-rich mineral fragment

Quartz (silicon dioxide, SiO₂), possibly milky quartz