Mixed

Rounded porous volcanic rock (likely scoria)

Scoria, vesicular basalt

Chrysocolla in Matrix

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

Decorative opal-like turtle mosaic

Likely imitation or assembled opal material; exact stones cannot be confirmed visually

Chrysocolla on Quartz

Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O) with Quartz (SiO2)

Pegmatite

Igneous Pegmatite (Quartz, Feldspar, Micas)

Greywacke

Lithic Sandstone (Greywacke)

Conglomerate

Conglomerate (Clastic sedimentary rock)

Pegmatite

Granitic Pegmatite

Gravel

Unconsolidated aggregate of mixed rock and mineral fragments

Bornite (peacock ore), likely copper sulfide specimen

Bornite, Cu₅FeS₄; possibly mixed with chalcopyrite

Copper Ore

Mixed copper sulfides/oxides in gangue matrix

Siltstone

Siltstone (composed of mixed silicate minerals and clay)

Common River Pebbles and Stones

Mixed natural stream gravel / siliciclastic pebbles

River Rock

Mixed composition, often quartzite, sandstone, or basalt

River Rocks and Pebbles

Mixed Silica-rich Sediments (SiO2 based)

Bauxite

Bauxite (Al2O3·2H2O mixed with iron oxides)

Gem Gravel

Alluvial Gem Gravel (Mixed silicate minerals)

Likely galena-bearing sulfide fragment

Galena (PbS), possibly mixed with sphalerite and/or chalcopyrite

Pyrite-bearing sulfide specimen (likely pyrite)

Pyrite, FeS₂; possibly mixed with pyrrhotite or chalcopyrite

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)

Likely quartz-bearing mineral aggregate

Quartz (SiO₂), possibly mixed with mica or feldspar

Dalmatian Stone (commonly called Dalmatian Jasper)

Peralkaline Rock (mixed Feldspar, Quartz, and Arfvedsonite)

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Educational Geologic Collection

Mixed Mineral and Rock Collection (Various compositions)

Orbicular Jasper (Ocean Jasper)

Silicon Dioxide (SiO2) with mineral inclusions

Tumbled granite or granitic gneiss

Granite, primarily quartz, alkali feldspar, plagioclase, and dark biotite/amphibole

Granite

Felsic intrusive igneous rock

Weathered quartz-rich rock, possibly granite or granitic pegmatite

Indeterminate quartz–feldspar aggregate; likely granite/pegmatite

Red Granite

Granite (Felsic intrusive igneous rock)

Pink granite

Coarse-grained granitic rock, chiefly orthoclase microcline feldspar, quartz, and dark biotite/amphibole

Conglomerate (pebble-to-cobble gravel)

Polymictic conglomerate; clast-supported conglomerate in a sandy or silty matrix

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Rhodonite

Rhodonite (Mn,Fe,Mg,Ca)SiO3

Pink Granite

Phaneritic Felsic Igneous Rock (composed primarily of K-Feldspar, Quartz, and Mica)

Gabbro (Water-worn pebble)

Gabbro

Asphalt (Bituminous pavement fragment)

Artificial conglomerate / Bitumen-Aggregate mixture

Pegmatite with Lepidolite and Feldspar

Pegmatite (containing K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2 and KAlSi3O8)

Amazonite with Smoky Quartz and Feldspar

Microcline (KAlSi3O8) with Quartz (SiO2)

Jasper-Quartz Conglomerate / Chert

Siliceous Sedimentary Rock (SiO2)

Jasper and Quartz Pebble

Silicon dioxide (SiO2) microcrystalline quartz variety

Mixed river stones and gravel

Polymictic alluvial clasts; individual pieces may include quartzite, granite, basalt, sandstone, limestone, and slate