Not A Geological Specimen

Quartz with Orthoclase Feldspar

Silicon Dioxide (SiO2) with Potassium Aluminum Silicate (KAlSi3O8)

Amygdaloidal Basalt with Quartz Infill

Amygdaloidal Basalt (SiO2 infill)

Chalcedony in Host Rock

Chalcedony (SiO2)

Greenschist

Greenschist (Chlorite Schist)

Quartz Cobble (River Pebble)

Quartz (Silicon Dioxide - SiO2)

Quartz Vein in Sandstone

Quartz (SiO2) in Clastic Sedimentary Rock

Dendritic Siltstone

Siltstone with Manganese Dendrites (MnO2)

Ironstone Nodule

Ironstone (Ferruginous Rock)

Heulandite with Stilbite

Heulandite-Ca ((Ca,Na)2-3Al3(Al,Si)2Si13O36·12H2O) and Stilbite-Ca (NaCa4(Si27Al9)O72·28H2O)

Decorative polished stone tile, likely white marble or limestone

Calcite-rich marble (CaCO₃), possibly veined limestone; exact identification requires testing

Conglomerate (possibly breccia)

Polymictic clastic conglomerate; rounded clasts in a dark, likely volcanic-lithic matrix

Banded gneiss (likely amphibolite-rich gneiss)

Banded gneiss; composition commonly quartz, feldspar, mica and/or amphibole

Fluorescent glassy mineral specimen, possibly hyalite opal

Hyalite (hydrated amorphous silica, SiO₂·nH₂O), tentative

Quartz vein in foliated metamorphic rock

Likely quartz-bearing schist or gneiss; visible crystal is quartz (SiO₂)

Chert (Flint)

Microcrystalline Quartz (SiO2)

Dark gray rounded cobble, likely basalt or fine-grained metamorphic rock

Likely basalt (plagioclase–pyroxene rock); exact identification requires testing

Quartz Geode

Crystalline Silicon Dioxide (SiO2) in a Geode

Rounded granite or granitic gneiss cobble

Granite, chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende

Weathered limestone

Calcite-rich limestone (primarily CaCO₃)

Garnet Schist

Almandine-bearing Mica Schist

Granite Pebble

Granite (Plutonic Igneous Rock)

Moqui Marble (Shaman Stone)

Ironstone Concretion (Fe2O3 with a sandstone core)

Schorl (Black Tourmaline)

Schorl (Sodium Iron Aluminum Borosilicate Hydroxide), NaFe3Al6(BO3)3Si6O18(OH)4

Granite pebble

Granite, typically quartz–feldspar–mica aggregate

Weathered metamorphic boulder, likely schist or gneiss

Quartz–feldspar–mica metamorphic rock; exact identification requires a fresh surface

Weathered volcanic rock, likely vesicular basalt or scoria

Basaltic volcanic rock; predominantly plagioclase, pyroxene, and possibly olivine with iron-oxide weathering

Petrified Wood

Silicified Wood (primarily SiO₂ / Silicon Dioxide)

Mica-rich granite (likely biotite granite)

Biotite granite; mainly quartz (SiO₂), alkali/feldspar, and biotite mica

Orbicular Granite

Orbicular Granidiorite / Plutonic Igneous Rock

Desert Rose

Gypsum (variety Selenite) or Barite, CaSO4·2H2O

Quartz Geode Fragment

Silicon Dioxide (SiO2)

Banded gneiss pebble

Foliated gneiss, typically quartz–feldspar–mica bearing

Banded Iron Formation (BIF)

Banded Iron Formation (predominantly Hematite and Chert)

Native Gold Nugget

Native Gold (Au)

Weathered iron-rich rock, possibly limonite-bearing sandstone

Limonite/goethite mixture, approximately hydrated iron oxides (FeO(OH)·nH₂O), possibly coating sandstone or ironstone

Banded Iron Formation (BIF)

Banded Iron Formation (SiO2 + Fe2O3)

Chert / Flint (Arrowhead Artifact)

Microcrystalline quartz (SiO2)

Garnet-Mica Schist

Garnetiferous Porphyroblastic Schist

Banded iron formation fragment (ironstone)

Banded iron formation; chiefly hematite/magnetite with chert (SiO₂)

Porphyry (Porphyritic Basalt / Porphyritic Andesite)

Porphyritic Igneous Rock

Weathered green metamorphic rock, possibly serpentinite or greenstone

Likely serpentinite (serpentine-group minerals) or chlorite/epidote-rich greenschist; exact identification requires testing

Metal Chain (Likely Steel or a Steel Alloy)

Steel (primarily iron and carbon); specific alloy unknown