Rock (Likely Sedimentary)

Banded Sedimentary Rock

Sedimentary rock with Liesegang banding

Granite River Cobble

Phaneritic Felsic Igneous Rock (Granite)

Granite

Felsic intrusive igneous rock (Granite)

Granite Pebble

Granitoid (Quartz-Feldspar dominant rock)

Quartzite River Cobble

Quartzite (primarily SiO2)

Quartzite (specifically an iron-stained or Carnelian-colored variety)

Silicon Dioxide (SiO2) with iron oxide inclusions

Dark gray river pebble, likely basalt or mudstone

Tentatively fine-grained basalt (plagioclase–pyroxene), though the image cannot exclude mudstone or weathered andesite

Mixed rounded stream pebbles

Most appear to be granitic and mafic igneous rocks, including granite, gneiss, basalt, and possibly quartzite; exact identification is uncertain from the image.

Porphyritic granite or granitic gneiss

Quartz–feldspar–mica granitoid; exact identification requires testing

Chert (Agatized/Chalcedony variety)

Microcrystalline Quartz (SiO2)

Likely petrified wood

Silicified wood, chiefly microcrystalline quartz (SiO₂)

Iron-Nickel Meteorite (Possible Chondrite or Oxidized Iron)

Siderite (Nickel-Iron) or Chondrite (Si/Fe composite)

Serpentinite (likely serpentinized ultramafic rock)

Serpentine-group minerals, chiefly antigorite/lizardite; commonly derived from peridotite

White Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Pink Stained Rock (Likely Quartzite or Sandstone with Iron Oxide Staining)

Quartzite (metamorphic) or Sandstone (sedimentary); coloration likely due to hematite or other iron oxides.

Limestone with possible fossil inclusions

Sedimentary Calcium Carbonate (CaCO3)

Weathered brown mineralized rock

Likely iron-stained quartzite or quartz-rich metamorphic rock; exact identification requires testing

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Weathered granite or granitic gneiss

Granite; predominantly quartz, feldspar, and mica, possibly altered to gneiss

Fossil Assortment and Geological Specimens

Various (including Ammonoidea)

Milky Quartz (Tumbled Pebble)

Silicon Dioxide (SiO2)

Granite Pebble

Granite (Phaneritic intrusive igneous rock)

Granite Pebble

Phaneritic Felsic Igneous Rock (Granite)

Sandstone (with possibly iron oxides and other minerals)

Sandstone

Petrified Wood (Silicified Wood)

Silicified Wood / Silicon Dioxide (SiO2)

Fossilized Bivalve Shell

Bivalvia (fossil specimen)

Milky quartz (likely weathered quartz vein)

Quartz, silicon dioxide (SiO₂)

Yellow Quartz (Citrine or Iron-stained Quartz)

Silicon Dioxide (SiO2)

Quartzite

Quartzite (SiO2)

Lichen-covered graywacke or granitic glacial cobble

Indeterminate; likely quartz–feldspar–mica rock, possibly weathered granite or granodiorite

Likely basalt fragment

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine

Quartzite (Milky Quartz pebble)

Silicon Dioxide (SiO2)

Sandstone

Arenite

Iron-stained quartz-bearing rock

Quartz (SiO₂), likely in a limonite/goethite-rich matrix

Petrified Wood

Silicified Wood (SiO2)

Granite River Pebble

Granite (Felsic Plutonic Rock)

Granite

Phaneritic Felsic Igneous Rock

Rounded river cobble, likely basaltic volcanic rock

Fine-grained mafic igneous rock; likely basalt or andesite

Unknown Organic Object (likely a berry or fruit)

Not applicable; this is not a geological specimen. If it were a cranberry, its scientific name would be Vaccinium macrocarpon; if a cherry, it would be Prunus avium or Prunus cerasus.

Quartz-rich pegmatite (likely granite/pegmatite boulder)

Coarse-grained felsic igneous rock, chiefly quartz (SiO₂), feldspar, and minor mica; exact identification requires testing

Chert (Jasper/Agate mix)

Microcrystalline Quartz (SiO2)

Chert (Jasper variety)

Silicon dioxide (SiO2) - Microcrystalline Quartz