Sedimentary Or Igneous Fragment

Sandstone (Weathered Fragment)

Clastic Sedimentary Rock

Gneiss

Gneiss (High-grade Metamorphic Rock)

Quartz-rich pegmatite fragment

Granite-family pegmatite; chiefly quartz (SiO₂), feldspar, and black mica (biotite)

Likely pink feldspar-rich granite or pegmatite

Granite/pegmatite; primarily quartz (SiO₂), alkali feldspar (KAlSi₃O₈), and plagioclase feldspar

Fine-grained mafic rock, likely basalt or altered basalt

Basalt; chiefly plagioclase feldspar and pyroxene, with possible chlorite/serpentine alteration

Likely weathered sandstone or iron-rich chert fragment

Indeterminate; probable quartz-rich sandstone (SiO₂) with iron-oxide cement, possibly chert

Pyrite

Iron Disulfide (FeS2)

Quartz Geode Pebble

Silicon Dioxide (SiO2)

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Smoky quartz crystal/rough fragment

Quartz (SiO₂), likely smoky quartz

Chert

Microcrystalline Quartz (SiO2)

Fossiliferous limestone (likely crinoidal or shell limestone)

Calcite-rich limestone; predominantly CaCO₃, with visible fossil fragments

Smoky quartz

Quartz (SiO₂), naturally irradiated brown variety

Milky quartz vein fragment

Quartz, silicon dioxide (SiO₂)

Chert (Flint) with Limestone Matrix

Silicon Dioxide (SiO2) within Calcium Carbonate (CaCO3)

Oolitic Limestone

Oolite (Sedimentary Calcium Carbonate)

Oolitic Limestone

Oolite (Sedimentary Calcium Carbonate)

Quartz (Milky / Clear Quartz Fragment)

Silicon Dioxide (SiO2)

Likely basaltic rock fragment

Fine-grained mafic igneous rock, probably basalt (plagioclase–pyroxene ± olivine)

Weathered limestone

Calcite-rich carbonate rock (mostly CaCO₃), possibly fossiliferous limestone

Chert (Banded)

Cryptocrystalline Silica (SiO2)

Chert (Arrowhead Fragment)

Chert / Microcrystalline Silicon Dioxide (SiO2)

Sandstone Concretion with Fossil Wood

Ferruginous Sandstone Concretion (SiO2 with Fe2O3 cement)

Coquina / Shelly Sandstone

Calcareous Sandstone / Coquina

Chert Nodule (Fossiliferous Chert)

Microcrystalline Quartz (SiO2)

Chert (Arrowhead Fragment)

Cryptocrystalline quartz (SiO2)

Weathered basalt or iron-rich river cobble

Basalt, likely with iron-oxide staining; exact identification requires testing

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Gravel / Limestone Fragment

Calcium Carbonate (CaCO3) / Fine-grained Sedimentary Rock

River Cobble (likely Basalt or Metagraywacke)

Non-specific water-worn lithic fragment

Calcite crystal fragment

Calcite (calcium carbonate, CaCO₃)

Tumbled blue glassy mineral, possibly sodalite or blue aventurine

Identification uncertain; likely sodalite (Na₈Al₆Si₆O₂₄Cl₂) or blue-dyed quartz/slag-like material

Weathered quartz-rich rock, likely granite or granitic gneiss

Granite (quartz–feldspar–mica aggregate), possibly weathered granitic gneiss

Pegmatitic granite, possibly potassium-feldspar-rich

Coarse-grained granite; mainly quartz (SiO₂), potassium feldspar (KAlSi₃O₈), plagioclase, and biotite/hornblende

Quartz-bearing granite or gneiss fragment

Granite/gneiss composed mainly of quartz (SiO₂), feldspar, and minor mica or ferromagnesian minerals

Pebble / Rounded Rock

Lithic fragment / Water-worn rock

Shale

Laminated Mudstone

River Cobble (Quartzite / Porphyritic Igneous Rock)

Siliceous rock / Water-worn lithic fragment

Metallic sulfide ore, likely pyrite-bearing rock

Pyrite (FeS₂), possibly with marcasite or other sulfides

Chert or chalcedony fragment

Microcrystalline quartz (SiO₂), likely ferruginous or jasper-like chalcedony

Cloudy Quartz / Quartz Tumble

Silicon Dioxide (SiO2)

Chert / Microcrystalline Quartz

Chert (SiO2)