Organic Material (Likely A Fruit Or Berry)

Siltstone with Quartz Vein

Siltstone (composed of Quartz and Clay minerals) with a hydrothermal Quartz vein (SiO2)

Chert (Iron-stained)

Microcrystalline Quartz (SiO2)

Weathered basalt or iron-rich volcanic rock

Mafic volcanic rock, likely basalt; exact identification requires testing

Chert (specifically Silex or Flint)

Microcrystalline Quartz (SiO2)

Polished/tumbled quartz-rich pegmatite

Quartz–feldspar pegmatite, with iron-oxide staining; chiefly SiO₂ and KAlSi₃O₈–NaAlSi₃O₈

Glacial erratic boulder

Likely weathered sandstone or quartzitic sandstone; exact identification requires a fresh surface and locality

Chert (and Quartzite)

Microcrystalline silica (SiO2)

Chert (specifically Flint or Novaculite variant)

Chert (Microcrystalline Quartz, SiO2)

Weathered quartz-rich rock, possibly chert or milky quartz

Mostly microcrystalline or crystalline quartz (SiO₂), identification uncertain from photograph

Brown chalcedony (likely carnelian/iron-stained quartz)

Microcrystalline quartz, SiO₂; brown coloration from iron oxides/hydroxides

Likely iron-rich chert or jasper

Microcrystalline quartz (SiO₂), variably stained by iron oxides/hydroxides

Banded Chert

Silicon dioxide (SiO2) with impurities

Chert (Jasper influence)

Microcrystalline Quartz (SiO2)

Riverstone Quartzite (Water-worn Siltstone/Quartzite)

Metamorphosed Quartz-rich Arenite (SiO2)

Green-and-gold apatite-bearing rock, possibly epidote skarn

Apatite-group mineral, commonly fluorapatite (Ca₅(PO₄)₃F), with probable epidote and quartz; exact identification requires testing

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3)

Chert (Iron-stained)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂)

Chert (Jasper/Flint variety)

Silicon Dioxide (SiO2)

Tumbled jasper (likely brecciated or orbicular jasper)

Microcrystalline quartz (SiO₂), with iron-oxide inclusions

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Chert (Flint/Gray Chalcedony)

Silicon Dioxide (SiO2)

Fossiliferous Shale Matrix

Clastic Sedimentary Rock with Brachiopod or Mollusk shell fragments

Chert (Iron-stained)

Chert (Microcrystalline and Cryptocrystalline Quartz, SiO2)

Pyrite

Iron Sulfide (FeS2)

Chert (Flint variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Chert (Quartz)

Microcrystalline Silica (SiO2)

Orange chalcedony (likely carnelian)

Microcrystalline quartz, SiO₂; iron-bearing chalcedony (carnelian)

Chert / Flint

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Siltstone with Quartz Vein

Siltstone (primarily SiO2, Al2O3, Fe2O3)

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly microcrystalline quartz (SiO₂), possibly with mica or feldspar

Breccia Pebble

Sedimentary Breccia

Biotite-bearing granite or gneiss

Felsic granitoid; chiefly quartz, feldspar, and biotite mica

Likely quartz-rich mineral fragment

Quartz (SiO₂), possibly iron-stained or included quartz

Rounded weathered pebble, likely sandstone or altered limestone

Indeterminate clastic carbonate/siliciclastic rock; exact identification requires a fresh surface and tests

Chert (Flint)

Microcrystalline Quartz (SiO2)

Mookaite Jasper

Silicified Radiolarite (SiO2)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Petrified Wood

Silicified wood (primarily quartz, SiO2)

Chert (Banded Variety)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Red Sandstone with Reduction Spot

Quartzose Sandstone with a Leach/Reduction Spot

Likely weathered river pebble

Indeterminate lithology; possibly fine-grained sandstone, siltstone, or chert