Sedimentary And Igneous (Mixed)

Polished black stone, likely obsidian or dark basalt

Volcanic glass (obsidian), possibly basalt; exact identification requires testing

Epidosite

Epidosite (composed primarily of Epidote and Quartz)

Olivine in Quartz/Feldspar Matrix (Peridotite or Granitic Pegmatite)

(Mg,Fe)2SiO4 (Olivine) with Quartz / Feldspar

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)

Bumblebee Jasper

Anhydrite with Sulfur, Hematite, and Orpiment (SiO2/CaSO4 mixture)

Polished/tumbled metallic sulfide specimen, likely pyrite

Pyrite (FeS₂), possibly mixed with chalcopyrite or other sulfides

Rounded gravel / river pebbles

Polymictic alluvial gravel, commonly quartz-, feldspar-, and lithic-rich clasts

Granite and Mixed Landscape Gravel

Plutonic Igneous Rock / Weathered Alluvium

Garnet crystals

Garnet-group silicates, likely almandine (Fe₃Al₂Si₃O₁₂)

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)

Dalmatian Jasper

Microcrystalline Quartz with Arfvedsonite/Tourmaline inclusions

Granite (weathered fragment)

Granite; chiefly quartz, alkali feldspar, plagioclase, and mica

Volcanic breccia or conglomeratic volcanic rock

Lithic volcanic breccia; possibly andesitic–basaltic matrix with feldspar-rich clasts

Weathered granite or granitic rock fragment

Granite; chiefly quartz, feldspar, and mica

Asphalt Concrete

Bituminous Concrete (Anthropic Rock)

Chert Pebble

Chert (Microcrystalline Quartz, SiO2)

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

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

Weathered rounded cobble

Indeterminate lithology; likely weathered sandstone or volcanic rock

Porphyritic granite pebble

Granite, chiefly quartz (SiO₂), alkali feldspar and plagioclase, with minor biotite/hornblende

Granitic Quartz or Pegmatite

Quartz with Orthoclase Feldspar (SiO2 + KAlSi3O8)

Tumbled jasper or chert pebble

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

Crushed limestone gravel

Limestone; predominantly calcite (CaCO₃), possibly dolomitic limestone with dolomite (CaMg(CO₃)₂)

Conglomerate

Conglomerate (clastic sedimentary rock)

Mixed beach gravel and cobbles

Polylithic alluvial or littoral clasts, including quartz, quartzite, chert, limestone, sandstone, and flint

Granite (Pink/Potassium Feldspar Granite)

Felsic Plutonic Rock (Potassium Feldspar, Quartz, Mica, and Amphibole)

River Siltstone / Mudstone Pebble

Siltstone (composed of mixed silicate and carbonate minerals)

Sandstone and Mixed Rock Assemblage

Clastic Sedimentary Rock / Quartz Arenite

Assorted gemstone jewelry

Mixed natural and synthetic gemstone cabochons and faceted stones; individual species cannot be determined reliably from this image

Mixed rounded rock pebbles

Likely granitic gneiss, basaltic rock, and quartz-rich granitic material; exact identification is uncertain from the image

Mixed rock and mineral gravel

Predominantly granite/granodiorite, basaltic rocks, quartz, and possible gneiss; exact identification is uncertain from the image

Mixed garnet crystal specimens

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

Mixed rounded gravel and pebbles

Polymictic clasts, likely including granite, basalt, quartzite, sandstone, and schist

Beach cobbles, predominantly basalt with vesicular volcanic fragments

Basalt (mafic volcanic rock), with possible altered basalt and minor feldspar/quartz-bearing pebbles

Mixed rock fragments, likely basalt and weathered granite

Basalt (mafic volcanic rock) and granitic fragments (quartz–feldspar–mica aggregate)

Weathered granite or granitic gneiss

Granite; chiefly quartz, feldspar, and mica, with iron-oxide weathering

Chakra Stone Bracelet

Mixed Mineral Assembly (Scoria, Amethyst, Lapis Lazuli, Turquoise/Howlite, Impression Jasper, Tiger's Eye, Carnelian, Red Jasper)

Polished brecciated jasper bracelet

Jasper, microcrystalline quartz (SiO₂), commonly with hematite and iron-oxide inclusions