Sedimentary Or Igneous Fragment

Weathered fossil shell fragment

Likely a fossilized bivalve or gastropod fragment; exact taxon cannot be determined from one view

Quartz Vein in Host Rock

Silicon Dioxide (SiO2) within Sedimentary or Igneous Matrix

Rock crystal quartz fragment

Quartz (silicon dioxide, SiO₂)

Yellow-green serpentine (likely)

Serpentine-group phyllosilicate, commonly lizardite or antigorite; approximate formula Mg₃Si₂O₅(OH)₄

Milky quartz

Quartz (silicon dioxide, SiO₂)

Milky quartz

Quartz (SiO₂), commonly called milky quartz

Weathered quartz-rich rock, likely granite or pegmatite fragment

Granite/pegmatitic granitoid; chiefly quartz (SiO₂), feldspar, and minor mica or iron oxides

Fossil shell fragment

Indeterminate molluscan bioclast, likely aragonite or calcite

Small quartz fragment (probable)

Quartz, SiO₂

Likely clear quartz fragment

Quartz (silicon dioxide, SiO₂)

Fossiliferous limestone / shell hash rock

Bioclastic limestone (calcarenite or coquina), dominantly CaCO₃

Granite (likely weathered granitic rock)

Granite; chiefly quartz (SiO₂), feldspar, and mica

Pebble

Lithic fragment / Rounded rock fragment

Conglomerate with Quartz Inclusions

Conglomerate (clastic sedimentary rock) with internal Quartz (SiO2)

Granite-like rock

Coarse-grained granitoid, likely granite or granodiorite

Weathered quartz-bearing metamorphic rock

Likely quartz–feldspar schist or gneiss, possibly with iron-oxide alteration

Quartz

Silicon Dioxide (SiO2)

Quartz (Clear Quartz)

Silicon Dioxide (SiO2)

Vesicular basalt (likely weathered scoria)

Basaltic volcanic rock; chiefly plagioclase, pyroxene, and iron-rich olivine

Fossilized Bone

Vertebrate Fossil Fragment (Calcium Phosphate / Hydroxyapatite)

Raw garnet-rich metamorphic rock

Likely garnet-bearing schist or garnetite; garnet-group silicates, commonly almandine (Fe₃Al₂Si₃O₁₂)

Likely reddish granite/porphyritic igneous rock fragments

Feldspar–quartz–mica aggregate, possibly pink granite or rhyolite

Generic Pebble

Lithic Fragment

Quartz Geode Fragment

Silicon Dioxide (SiO2)

White quartz pebble

Quartz (silicon dioxide, SiO₂)

Quartz (Milk or Clear Variety)

Silicon Dioxide (SiO2)

Chert Breccia

Brecciated Chert

Vesicular basalt (possibly slag-contaminated)

Basalt; chiefly plagioclase and pyroxene, with possible olivine and secondary minerals

Quartz

Silicon Dioxide (SiO2)

Exposed aggregate concrete (stone-chip surface)

Portland-cement concrete containing natural aggregate; not a natural rock

Likely milky quartz

Quartz (silicon dioxide, SiO₂)

Small rounded mineral/rock fragment

Indeterminate; possibly quartz-rich stone or feldspar

Small rough mineral/rock fragment

Indeterminate; possibly quartz-bearing rock or weathered feldspar

Small rounded stone or mineral fragment

Indeterminate; likely a common quartz- or feldspar-bearing silicate fragment

Quartz (Smoky/Milky variety)

Silicon Dioxide (SiO2)

Quartz (Iron-stained or Chalcedony varieties)

Silicon Dioxide (SiO2)

Magnetite (Iron Ore)

Magnetite (Fe3O4)

Mixed rock and mineral specimen collection

Mostly undetermined from the photograph; apparent quartz-rich rocks, sandstone, granite/gneiss, and possibly iron-oxide-bearing specimens

Quartz

Silicon Dioxide (SiO2)

Fossil oyster shell

Fossilized bivalve, likely Ostrea or Crassostrea; calcite (CaCO₃) shell

Gneiss

Gneiss (High-grade Regional Metamorphism)

Pyrite

Iron Sulfide (FeS2)