Sedimentary And Igneous (Mixed)

Amygdaloidal Basalt

Amygdaloidal Mafic Volcanic Rock

Rhyolitic Tuff

Rhyolitic Tuff / Pyroclastic rock

Landscaping Gravel / River Rock

Polymictic Gravel Aggregates

Conglomerate

Conglomerate (clastic sedimentary rock)

Concrete Paver (Artificial Cementitious Rock)

Hydrated Portland Cement Aggregate

Tumbled yellow-brown quartzite or jasper

Quartzite, predominantly microcrystalline quartz (SiO₂), possibly iron-stained jasper

Chrysocolla on Matrix

Hydrated copper silicates ((Cu,Al)2H2Si2O5(OH)4·nH2O)

Sodalite

Sodalite (Na8(Al6Si6O24)Cl2)

Granite Cobble

Phaneritic Felsic Igneous Rock (Granite)

Weathered granite boulder

Granite, a quartz–feldspar-rich intrusive igneous rock

Weathered quartz-rich river pebble

Likely altered granite or granitic gneiss, composed mainly of quartz, feldspar, and minor mica/iron oxides

Black granite (likely polished gabbro or diabase)

Granitoid rock dominated by feldspar, quartz, and dark mafic minerals; exact identification requires testing

Mixed polished gemstones and minerals

Likely agate/chalcedony (SiO₂), quartz, jasper, and possibly aventurine or obsidian; exact identification requires individual testing.

Epidote in Quartz

Epidote (Ca2(Al2,Fe3+)3(SiO4)3(OH)) / Quartz (SiO2)

Granite and Mixed Landscape Gravel

Plutonic Igneous Rock / Weathered Alluvium

Gravel

Unconsolidated aggregate of mixed rock and mineral fragments

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)

Landscaping river rock (mixed rounded pebbles)

Mixed lithologies; likely water-worn quartzite, granite, and other silicate pebbles

Jasper Rose Quarts / Ferruginous Quartz

Silicon Dioxide (SiO2) with Hematite inclusions

Weathered granitic rock fragment

Likely granite or granodiorite; quartz–feldspar–mica aggregate

Polished hematite

Hematite (Fe₂O₃), likely a tumbled iron-oxide specimen

Mixed stream gravel and cobbles

Polylithic alluvial deposit; individual clasts are not identifiable at this resolution

Yellow Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Asphalt (Bituminous pavement fragment)

Artificial conglomerate / Bitumen-Aggregate mixture

Quartz-rich pegmatite (likely rose/iron-stained quartz)

Quartz, SiO₂, in a coarse granitic pegmatite matrix; possibly with feldspar and mica

Granite (Pink/Alkali Feldspar Granite)

Plutonic Igneous Rock (Granite)

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)

Rainbow Hematite (Man-made/Treated)

Tumbled Hematite with Titanium/Anodized coating (Iron(III) oxide, Fe2O3)

Concrete aggregate surface

Human-made cementitious composite; primarily calcium-silicate-hydrate cement with mixed silicate aggregate

Glauconitic Sandstone (Greensand)

Glauconitic Quartz Arenite (Formula: (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Mixed Quartz and Mineral Gravel

Silicon Dioxide (SiO2) and assorted silicate minerals

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

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

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Glauconitic Sandstone

Glauconitic Sandstone (Quartz with Glauconite)

Mahogany Obsidian

Volcanic glass containing Magnetite/Hematite

Mixed garnet crystal specimens

Garnet-group silicates, likely almandine–spessartine with possible grossular/pyrope varieties; general formula X₃Y₂(SiO₄)₃

Red Jasper

Silicon Dioxide (SiO2) - variety of Chalcedony