Sedimentary Rock (Possibly Composed Of Various Minerals)

Weathered quartz-rich stone, possibly fossiliferous limestone

Indeterminate; likely calcite-rich limestone (CaCO₃) or weathered quartz-bearing rock

Gravel / Crushed Stone

Aggregate (mixed mineral rock fragments)

Rhodonite

Rhodonite, manganese inosilicate — MnSiO₃; the specimen may include quartz, feldspar, and black manganese-oxide minerals in the matrix

Howlite

Calcium Borosilicate Hydroxide (Ca2B5SiO9(OH)5)

Quartzite

Quartzite

Banded agate or jasper fragment

Microcrystalline quartz, SiO₂ (likely iron-stained chalcedony)

Jasper with Quartz Veining

Silicon Dioxide (SiO2) with iron oxide impurities

Jasper

Microcrystalline Quartz (SiO2)

Dark-colored Igneous Rock (likely Basalt or Diabase)

Basalt (extrusive igneous) or Diabase (intrusive igneous)

Fossilized ammonite (likely weathered ammonite cross-section)

Ammonoidea; commonly Jurassic–Cretaceous ammonite fossils replaced by calcite or aragonite

Granite

Phaneritic Plutonic Igneous Rock

Rough amber-like brown mineral specimen

Uncertain from photograph; possibly iron-stained quartz, common opal, or resinous amber

Leopard Skin Jasper

Silicified Rhyolite or Orbicular Jasper (SiO2)

Basalt (or similar Mafic Igneous Rock)

Basalt

Chert / Jasper

Cryptocrystalline Silica (SiO2)

Conglomerate

Clastic sedimentary rock (Psephite)

Purple Conglomerate

Polymictic Conglomerate

Lapis Lazuli

Lapis Lazuli (Complex rock mainly composed of Lazurite, Calcite, and Pyrite)

Sandstone with Ironstone Banding

Clastic Sandstone (composed of Quartz with Hematite/Limonite bonding)

Serpentinite

Serpentinite (composed primarily of mineral group (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4)

Limestone

Calcium Carbonate (CaCO3)

Geode (Quartz / Chalcedony Geode)

SiO2 (Silicon Dioxide)

Likely weathered quartz-rich rock fragment

Uncertain; possibly granitic pegmatite or quartz-bearing metamorphic rock

Goldstone (blue-goldstone–style glass) beads

Artificial aventurine glass, typically silica glass with copper inclusions; not a natural mineral

River Stone (likely Mudstone or Siltstone)

Lutite (Clastic sedimentary rock composed of clay and silt-sized particles)

Milky Quartz Pebble

Silicon Dioxide (SiO2)

Druzy Quartz

Silicon Dioxide (SiO2)

Limonite Concretion

Limonite (Hydrated Iron Oxide) FeO(OH)·nH2O

Greenschist (Chlorite Schist)

Greenschist (Metamorphic rock dominated by chlorite, actinolite, and epidote)

Slate

Foliated Metamorphic Rock (composed primarily of silica and alumina with iron and magnesium)

Red Breccia Jasper

Silicon Dioxide (SiO2) with hematite and various mineral inclusions

Sandstone Cobble with Iron Staining

Arenite with Limonite/Hematite staining

Granite (likely biotite granite or granodiorite)

Coarse-grained plutonic rock composed mainly of quartz, feldspar, and dark mica/amphibole

Granite or granitic gneiss

Felsic granitoid, chiefly quartz, feldspar, and mica; possibly weakly foliated gneiss

Pyrite (iron pyrite)

Iron sulfide, FeS₂; commonly called fool’s gold

Botryoidal Chalcedony with Calcite

Chalcedony (SiO2 with accessory minerals, likely CaCO3)

Banded Agate

SiO2 (Silicon Dioxide)

Agate

Silicon Dioxide (Chalcedony), SiO2

Granite Gneiss

Granitic Gneiss

Granite

Phaneritic Intrusive Igneous Rock (Quartz-Feldspar dominant)

Chert (Arrowhead Preform or Point)

Chert (Microcrystalline Quartz, SiO2)

Fossilized Shark Tooth (Partial)

Elasmobranchii (fossil tooth fragment)