Not A Rock Or Mineral

Rough Emerald in Matrix

Beryl (Be3Al2Si6O18) with trace Chromium/Vanadium

Quartz with Schist Matrix

Crystalline Silicon Dioxide (SiO2) in micaceous schist

Sandstone (Ferruginous)

Ferruginous Sandstone (SiO2 with Fe2O3)

Siltstone / Slate

Siltstone / Low-grade Slate

Lake Superior Agate

Silicon Dioxide (Chalcedony / Quartz)

Dragonstone (Brecciated Basalt/Diabase with Epidote and Quartz)

Brecciated mafic igneous rock

Rounded weathered rock, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; precise identification requires testing

Ocean Jasper

Orbicular Jasper (Silicon Dioxide with impurities), SiO2

Amethyst

Silicon Dioxide (SiO2)

Mixed tumbled gemstone collection

Varied minerals, likely including amethyst, sodalite/lapis lazuli, quartzite or aventurine, jasper, and agate/chalcedony

Quartz Breccia with Iron Staining

Tectonic or Sedimentary Breccia (SiO2 with Fe2O3)

Schist

Mica Schist

Banded Gneiss

Gneiss (High-grade Metamorphic Rock)

Conglomerate

Conglomerate

Gneiss

Gneissic Metamorphic Rock

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in Geode

Schist

Mica Schist

Ironstone Concretion

Siderite or Ferruginous Concretion (FeCO3 or Iron Oxides)

White Howlite

Howlite (Hydrated calcium borosilicate, Ca2B5SiO9(OH)5)

Milky Quartz

Silicon Dioxide (SiO2)

Amethyst (as a jewelry accent)

Amethyst (Silicon Dioxide SiO2 with Iron impurities)

Quartz (Chert/Quartzite variant)

Silicon Dioxide (SiO2)

Dalmatian Jasper

Peralkaline rhyolite with arfvedsonite inclusions

Shale with Iron Staining

Fissile Mudrock (Sedimentary Rock)

Vesicular Basalt with Secondary Mineral Inclusions

Aphanitic Mafic Igneous Rock (primarily Plagioclase and Pyroxene)

Amphibolite (specifically Hornblende Schist/Gneiss)

Amphibole-rich Metamorphic Rock

Sandstone

Arenite (SiO2 based)

Sandstone (Calcareous Sandstone)

Calcareous Sandstone (primarily SiO2 with CaCO3 cement)

Dalmatian Stone

Dalmatian Jasper (Aplitic Rock)

Thunder Egg (Agate Core)

Cryptocrystalline Quartz (SiO2) in Rhyolite/Perlite Matrix

Weathered granitic rock, likely granodiorite

Granodiorite: quartz, plagioclase feldspar, potassium feldspar, and biotite/hornblende

Turquoise (set in silver jewelry)

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrated copper and aluminum phosphate)

Turquoise

CuAl6(PO4)4(OH)8·4H2O

Dark gray weathered pebble, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Sandstone

Clastic sedimentary rock (primarily SiO2)

Leopard Jasper

Microcrystalline Quartz (SiO2)

Sandstone

Arenite (SiO2 dominated sandstone)

Sandstone (Red/Brown Pebble)

Arenite / Quartzarenite (SiO2 with iron oxides)

Sandstone

Clastic sedimentary rock (primarily quartz arenite)

Sandstone

Arenite (predominantly SiO2)

Sandstone

Arenite (SiO2 principal)

Quartz Geode Fragment

Silicon Dioxide (SiO2)