Mixed: Igneous And Sedimentary

Rounded gray stone, likely weathered chert or quartz-rich river pebble

Chert (microcrystalline SiO₂), tentative

Tumbled jasper or chalcedony pebble

Microcrystalline quartz (SiO₂), likely jasper/chalcedony with iron-oxide staining

Chrysocolla

Hydrated copper phyllosilicate, Cu2-xAlx(H2-xSi2O5)(OH)4·n(H2O)

Pink Granite

Phaneritic intrusive igneous rock with dominant Alkali Feldspar

Weathered granite pebble

Granite, predominantly quartz–feldspar–mica aggregate

Pink Granite

Felsic Plutonic Rock (Granite)

Mahogany Obsidian

Volcanic Glass with Hematite/Magnetite inclusions (SiO2 + Fe2O3)

Pink Granite (Crystalline Granite)

Igneous Intrusive Rock (Felsic Plutonic)

Conglomerate

Conglomerate (clastic sedimentary rock)

Pegmatite with Quartz and Feldspar

Intrusive Igneous Rock

Pink Granite

Granite (Felsic Plutonic Igneous Rock)

Mixed Mineral Assortment (Pyrite, Kyanite, Agate, Jasper)

FeS2 (Pyrite), Al2SiO5 (Kyanite), SiO2 (Agate/Jasper)

Peacock Ore

Bornite (Cu5FeS4)

Lapis Lazuli

Lapis Lazuli (Complex rock primarily composed of Lazurite (Na,Ca)8[(SO4,S,Cl)2|(AlSiO4)6], Calcite, and Pyrite)

Fuchsite Schist

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2) in Schist

Pyrite in Quartz

FeS2 (Iron Pyrite) with SiO2 (Quartz)

Sandstone and Mixed Rock Assemblage

Clastic Sedimentary Rock / Quartz Arenite

Ironstone Pebble

Ferruginous sedimentary rock (Fe2O3 / FeO(OH) mixed with SiO2)

Agate

Silicon dioxide (Chalcedony), SiO2

Tumbled Agate

Silicon dioxide (SiO2)

Mixed pebble collection, including likely flint, quartzite, and fossil material

Varied silicate rocks; visible specimen may include chert (microcrystalline SiO₂), quartzite, and a possible fossil

Agate Bookend / Quartz Geode

Silicon Dioxide (SiO2)

Concrete

Anthropogenic Sedimentary Rock (Hydrated Calcium Silicate)

Green-and-gold apatite-bearing rock, possibly epidote skarn

Apatite-group mineral, commonly fluorapatite (Ca₅(PO₄)₃F), with probable epidote and quartz; exact identification requires testing

Granodiorite

Granodiorite (phaneritic intrusive igneous rock)

Agate Nodule

Silicon Dioxide (Quartz/Chalcedony), SiO2

Weathered iron-rich rock, possibly hematite-bearing breccia

Hematite (Fe₂O₃)-rich lithic fragment; exact host rock is uncertain from the image

Quartz-rich conglomeratic sandstone

Lithic arkose/conglomerate, dominated by quartz and feldspar grains

Limonite (Ironstone Concretion)

Limonite (Hydrous Ferric Oxides mixed with Goethite)

Mixed collection of Quartz varieties, Chalcedony, and metamorphic pebbles

Mixed gemstones (primarily Silicon Dioxide - SiO2)

Tumbled chert or flint

Microcrystalline quartz (SiO₂), commonly chalcedony with possible iron-oxide inclusions

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Mixed rock fragments, likely basalt and weathered granite

Probable mafic volcanic rock (basalt) with granitoid fragments; exact identification is uncertain from the image

Raw tourmaline crystal (probable schorl)

Tourmaline group; likely schorl, NaFe3+Al6(BO3)3Si6O18(OH)4

Fossiliferous Limestone

Limestone (CaCO3 with Limonite/Goethite staining)

Banded Iron Formation (Jaspilite / Hematite Jasper)

SiO2 + Fe2O3 (Quartz with Hematite/Magnetite)

Common River Pebbles and Stones

Mixed natural stream gravel / siliciclastic pebbles

River Rock

Mixed composition, often quartzite, sandstone, or basalt

Siltstone

Siltstone (composed of mixed silicate minerals and clay)

River Rocks and Pebbles

Mixed Silica-rich Sediments (SiO2 based)

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Pea Gravel / River Gravel

Unconsolidated Clastic Sedimentary Aggregate