Igneous And Metamorphic Derivative (Weathered)

Likely rough quartz with iron-oxide staining

Quartz (SiO₂), possibly with iron-oxide inclusions or surface staining

Serpentine (Serpentinite)

Serpentine group ((Mg,Fe,Ni,Al,Zn,Mn)3(Si,Al)2O5(OH)4)

Blue Apatite

Apatite, Ca5(PO4)3(F,Cl,OH)

Quartz (Agate/Jasper pebble)

Silicon Dioxide (SiO2)

Smoky Quartz

Silicon Dioxide (SiO2)

White quartz pebble

Quartz (SiO₂), likely massive milky quartz

Milky quartz pebble

Quartz, silicon dioxide (SiO₂)

Milky quartz vein in altered host rock

Quartz (SiO₂), likely with feldspar, mica, and iron-oxide alteration

Tumbled quartz-rich pebble, possibly citrine or iron-stained quartz

Quartz, silicon dioxide (SiO₂), with probable iron-oxide inclusions

Quartz Pebble

Silicon Dioxide (SiO2)

Unidentified Rock Fragment

Unknown

Quartz Pebble

Silicon Dioxide (SiO2)

Rounded quartz-rich pebble, likely granite or granitic gneiss

Granite-derived granitoid; mainly quartz (SiO₂), feldspar, and minor mica

Iron-stained quartz pebble

Quartz (SiO₂), likely microcrystalline or massive quartz with goethite/limonite staining

Quartz-rich rock, possibly milky quartz or quartzite

Quartz (SiO₂), potentially quartzite if the grains are fused

Small weathered mineral/rock fragment

Indeterminate; possibly quartz-bearing feldspathic rock or calcite-rich specimen

Hematite

Iron Oxide (Fe2O3)

Quartz (Smoky/Brown variety)

Silicon dioxide (SiO2)

Pyrite

Iron Sulfide (FeS2)

Milky quartz

Quartz (silicon dioxide, SiO₂)

Weathered quartz-rich river cobble

Likely granitic or quartzitic rock; exact identification is uncertain from the photograph

Weathered volcanic rock, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; primarily plagioclase feldspar, pyroxene, and possibly olivine or iron oxides

Possible granite or granitic gneiss pebble

Granite; primarily quartz, feldspar, and mica

Quartz pebble

Silicon dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Gabbro with quartz/feldspar veins

Gabbro, likely with leucocratic quartz–feldspar pegmatitic material

Milky quartz pebbles

Quartz (silicon dioxide, SiO₂)

Quartz-rich pegmatite (possibly quartz–feldspar rock)

Granite pegmatite; chiefly quartz (SiO₂) with feldspar and minor mica/iron staining

Weathered quartz-rich stone, possibly quartzite

Quartzite (mostly SiO₂), possibly quartz-bearing sandstone or granite fragment

Weathered quartz-rich pebble

Likely quartzite or quartz-rich sandstone; exact identification is uncertain from the photograph

Gneiss (Metamorphic Cobble)

Gneiss

Greenstone

Metamorphosed Mafic Igneous Rock

Rainbow Moonstone (White Labradorite)

Labradorite (White varieties with Schiller effect), (Na,Ca)(Al,Si)4O8

Quartz Pebble (Citrine-colored or Stained Quartz)

Silicon Dioxide (SiO2)

Hematite

Hematite (Fe2O3)

Milky Quartz

Silicon Dioxide (SiO2)

River Gravel

Polymictic gravel and pebble aggregate

Quartz Pebble

Silicon Dioxide (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

Coarse Sand or Fine Gravel

Detrital Sedimentary Fragments (mostly SiO2)

Quartz Mineral

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)