Sedimentary Or Igneous Fragment

Granite

Intrusive Igneous Rock

Blue-gray stone fragment, possibly slate or fine-grained basalt

Undetermined; appearance is consistent with slate (fine-grained metamorphosed mudstone), but the image is insufficient for reliable identification.

Rock Crystal Quartz

Quartz (SiO₂)

Conglomerate

Conglomerate (clastic sedimentary rock)

Blue crystal/mineral specimen (possibly blue quartz or dyed stone)

Uncertain from photograph; possible quartz, SiO₂, or a blue copper-bearing mineral

Fossiliferous Limestone

Biogenic Sedimentary Rock (primarily CaCO3 with fossil fragments)

Basalt (Road Gravel)

Basalt (Mafic Extrusive Igneous Rock)

Unidentified weathered rock fragment

Likely limestone or sandstone; exact identification is not possible from the photograph

Fossiliferous limestone

Bioclastic carbonate rock, chiefly calcite (CaCO₃)

Iron-rich brown stone, possibly weathered chert or ironstone

Undetermined; likely iron-oxide-bearing silica-rich rock (chert/ironstone)

River Pebble

Polished Quartzite or Mixed Lithology

Tumbled quartz-rich rock, possibly calcite or sandstone

Indeterminate from photograph; likely microcrystalline quartz (SiO₂) or calcite (CaCO₃)

Weathered granite or granitic gneiss fragment

Coarse quartz–feldspar–mica aggregate; possibly weakly foliated gneiss

Coarse-grained granite (likely granitic beach rock)

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

Likely polished/tumbled dark mineral or glassy rock fragment

Indeterminate from image; possibly hornblende, schorl tourmaline, or obsidian

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Weathered sandstone fragment

Quartz-rich sandstone, likely ferruginous sandstone

Likely tumbled quartz or feldspar fragment

Quartz (SiO₂) or feldspar-group silicate

Fossiliferous Limestone

Biogenic Sedimentary Rock / CaCO3 with fossil fragments

Quartz with Iron Staining

Silicon Dioxide (SiO2)

Granite Gravel (Pebble)

Intrusive Felsic Igneous Rock

Milky quartz fragment

Quartz (silicon dioxide, SiO₂)

Unidentified gray mineral/rock fragment

Indeterminate from image; possibly quartz-rich material or mica-bearing schist

Breccia

Clastic Breccia (General mineral composition depends on fragments, often SiO2 or CaCO3)

Porous sandstone or weathered limestone fragment

Indeterminate clastic carbonate/siliciclastic rock; likely quartz-rich sandstone or calcarenite

Granite

Granite; primarily quartz, feldspar, and mica

Weathered brown rock fragment, possibly iron-rich basalt or breccia

Tentatively basaltic rock; exact identification requires testing

Weathered gray rock fragment

Likely granitic or volcanic feldspathic rock; exact identification is uncertain from the image

River Stone / Pebble

Clastic Sediment (composed largely of Quartz, Feldspar, and various rock fragments)

Volcanic Tuff (Breccia)

Pyroclastic Tuffaceous Rock

Rounded iron-rich pebble

Likely ferruginous sandstone or ironstone; exact identification is uncertain from the photograph

Paving-concrete aggregate with a rounded stone

Polymictic gravel aggregate; the central clast appears to be weathered sandstone or volcanic rock

Likely limestone or calcareous fossil fragment

Calcite-rich carbonate rock; possibly bioclastic limestone (CaCO₃)

Small metallic-looking mineral/rock fragment

Indeterminate from image; possibly galena, hematite, or metallic slag

Weathered quartz-rich pebble, possibly quartzite or chert

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

Quartz / Common Opal

Silicon Dioxide (SiO2)

Fossiliferous Limestone (Coquina / Shell Conglomerate)

Bioclastic Limestone (composed primarily of CaCO3)

Calcite fragment

Calcite, calcium carbonate (CaCO₃)

Likely quartz-rich sedimentary pebbles

Quartz arenite or chert-like siliceous rock; exact identification is uncertain from the photograph

Concrete-embedded rock fragment, likely weathered granite or gneiss

Probable granitic silicate assemblage: quartz, feldspar, and dark mica/amphibole

Quartz Crystal Fragment

Silicon Dioxide (SiO2)

Slate fragment

Slate; predominantly fine-grained mica/clay minerals, commonly muscovite, chlorite, and quartz