Industrial By Product

Blue-gray kyanite

Kyanite (Al₂SiO₅)

Pumice

Pumice, vesicular volcanic glass (typically silica-rich rhyolite or dacite composition)

Tumbled amethyst

Quartz, crystalline silicon dioxide (SiO₂), purple variety colored mainly by iron impurities and irradiation

Pumice and Scoria

Vesicular Volcanic Rock (Pumice: Silicic / Scoria: Mafic)

Desert Rose

Gypsum (CaSO4-2H2O) or Baryte (BaSO4)

Vesicular scoria (likely iron-rich volcanic scoria)

Scoria, typically basaltic to andesitic; chiefly plagioclase, pyroxene, olivine, and volcanic glass

Milky quartz pebble

Quartz (SiO₂), commonly called milky quartz

Marble

Recrystallized Calcite (CaCO3)

Blue Kyanite

Kyanite (Al2SiO5)

Pumice (likely weathered/water-worn)

Vesicular volcanic glass

Limestone

Calcium Carbonate (CaCO3)

Pumice

Pumice (Amorphous volcanic glass)

Pumice

Vesicular volcanic glass

Pumice

Pumice (Vesicular volcanic glass)

Pumice

Pumice (Vesicular volcanic glass / Rhyolite or Trachyte)

Weathered basaltic rock

Basalt, likely altered basalt (plagioclase–pyroxene ± olivine; possible iron-oxide staining)

Limonite (Iron-rich Gossan/Laterite)

FeO(OH)·nH2O (Hydrated Iron Oxide)

Hematite

Iron(III) oxide (Fe2O3)

Hematite (Tumbled)

Iron(III) oxide (Fe2O3)

Greenstone (likely serpentinite or greenstone pebble)

Serpentinite-rich ultramafic rock; commonly dominated by serpentine-group minerals, with possible chlorite, actinolite, or magnetite

Iron-rich meteorite candidate

Undetermined meteoritic iron–nickel material; possibly an ordinary chondrite or weathered iron meteorite

Carved pyrite frog or toad

Pyrite (iron disulfide, FeS₂), likely a carved massive aggregate

Hematite (Iron Ore)

Hematite (Fe2O3)

Hematite

Iron(III) oxide (Fe2O3)

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Hematite

Iron(III) oxide (Fe2O3)

River Stone (likely Siltstone or fine-grained Basalt)

Clastic Sedimentary (Siltstone) or Mafic Igneous (Basalt)

Serpentinite pebble

Serpentinite, composed chiefly of serpentine-group minerals (lizardite, chrysotile, antigorite), with possible magnetite and chlorite

Dark gray fine-grained rock, possibly slate

Slate (fine-grained metamorphosed mudstone; identification uncertain from image)

Travertine

Calcium Carbonate (CaCO3)

Granite

Intrusive Igneous Rock (composed mainly of quartz, alkali feldspar, and plagioclase)

Goethite

Goethite (FeO(OH))

Hematite (Specularite)

Fe2O3 (Iron(III) oxide)

Weathered quartz-rich rock fragment

Likely quartz-bearing vein rock, possibly quartzite or silicified breccia; exact identification requires testing

Yellow-green serpentine pebble

Serpentinite; chiefly antigorite, lizardite, or chrysotile Mg₃Si₂O₅(OH)₄

Weathered basalt or volcanic scoria fragment

Basaltic volcanic rock; chiefly plagioclase, pyroxene, and iron-rich oxides

Weathered mafic rock, likely basalt or gabbro

Basalt–gabbroic rock; chiefly plagioclase feldspar and pyroxene, with possible olivine and magnetite

Sandstone (likely Fossiliferous Sandstone)

Clastic sedimentary rock (primarily SiO2)

Iron-rich breccia (likely limonite/goethite-stained rock)

Ferruginous breccia; iron oxides/hydroxides such as goethite (FeO(OH)) and limonite, with unidentified rock fragments

Slate

Metamorphic rock (fine-grained, foliated)

Ambergris (Marine Coprolite/Subfossil)

Marine organic coprolite / Ambergris (Physeter macrocephalus metabolite)

Iron-rich weathered rock (probable limonite/goethite)

Limonite, a mixture dominated by goethite (FeO(OH)) and related hydrated iron oxides