Mineral (Sedimentary Context)

Pyrite-bearing quartz vein (likely pyrite ore)

Pyrite, FeS₂, with abundant quartz (SiO₂) and possibly chalcopyrite

Chert (Arrowhead Fragment)

Microcrystalline Quartz (SiO2)

Sandstone (Water-worn Cobble)

Arenite (variable composition, primarily SiO2)

Rounded gray stone, likely quartz-rich granitic rock

Probable granite or granitic gneiss; mainly quartz, feldspar, and mica

Baked-clay ceramic fragment (likely brick or pottery)

Fired clay, primarily aluminosilicate minerals; not a natural rock

Veined gneiss

Felsic to mafic banded gneiss, chiefly quartz–feldspar–biotite/hornblende

Ironstone Concretion (Limonite/Goethite)

Ferruginous Sandstone or Limonite (FeO(OH)·nH2O)

Efflorescence (on Clay Brick)

Crystalline salt deposits (typically Sodium Sulfate Na2SO4, Calcium Carbonate CaCO3, or Potassium Sulfate K2SO4)

Stromatolite (stromatolitic limestone)

Laminated microbial carbonate, chiefly calcite (CaCO₃); precise species or age cannot be determined from the photo

Chert (flint) fragment

Microcrystalline quartz (SiO₂), commonly called chert; “flint” is a variety of chert

Red Jasper

Silicon Dioxide (SiO2) with Hematite inclusions

Uncertain fine-grained rock or mineral-bearing specimen

Indeterminate; possible quartz- or feldspar-bearing matrix with reflective grains

Jasper Marble

Silicon Dioxide (SiO2) with Impurities

Chert (Arrowhead Fragment)

Silicon Dioxide (SiO2)

Chalcedony / milky quartz flake

Microcrystalline quartz (SiO₂), likely chalcedony; possibly a worked quartzite or chert fragment

Shale with Pyrite

Clastic sedimentary rock containing Iron Disulfide (FeS2)

Milky Quartz Pebble with Iron Inclusions

Silicon Dioxide (SiO2) with iron oxide impurities

Unidentified small rock or mineral fragment

Indeterminate from the blurred image; possibly quartz-rich stone, feldspar, or weathered concrete-like geological material

Zebra Jasper

Tetragonal Silicon Dioxide (Quartz) with impurities

Red Jasper (Mookaite style)

Silicon Dioxide (SiO2) with iron oxide impurities

Chert (Septarian or Nodular variety)

Microcrystalline Quartz (SiO2)

Chalcedony Geode / Agate Nodule

Cryptocrystalline Quartz (SiO2)

Ferruginous Sandstone (Gritstone)

Clastic sedimentary rock with iron-rich cement (FeO(OH)·nH2O)

Flint (chert) hand axe

Cryptocrystalline silica (SiO₂), worked into a bifacial stone tool

Red Sandstone

Arenite (primarily composed of SiO2 with Fe2O3 cement)

Wishing Rock (Quartz Vein in Host Rock)

Silicon dioxide (SiO2) vein in various host rocks

Limonite-pseudomorph after Pyrite (Prophecy Stone)

Goethite and Limonite secondary minerals (FeO(OH)·nH2O) replacing Pyrite (FeS2)

Red Sandstone

Arenite (primarily SiO2 with Fe2O3)

Sandstone Concretion

Sandstone (Sedimentary Rock) with silica or calcite cement

Leopard Skin Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Red Sandstone

Arenite (Ferruginous Sandstone)

Kidney Stone

Calcium oxalate, uric acid, struvite, or cystine

Fossilized bone fragment, possibly mammalian long bone

Mineralized bone (commonly apatite, Ca₅(PO₄)₃(OH,F,Cl), replacing original bone)

Chert (with Drusy Quartz Pocket)

Silicon Dioxide (SiO2)

Chert / Flint Arrowheads

Cryptocrystalline Quartz (SiO2)

Weathered sandstone fragment

Quartz-rich sandstone, possibly ferruginous sandstone

Sandstone Concretion

Limonitic Sandstone Concretion

Mica Schist

Mica Schist (Quartz-Mica Schist)

Ironstone Concretion (Moqui Marble)

Iron-oxide concretion (Fe2O3 / FeO(OH))

Black Jasper

Black Jasper (Silicate mineral - SiO2)

Sandstone (Nut-stone / Cup-stone artifact)

Quartz Arenite / Worked Sedimentary Rock

Ferruginous Sandstone

Arenite with Iron-Oxide Cement (FeO(OH)·nH2O / Fe2O3)