Industrial By Product

Weathered volcanic rock, likely andesite or basalt

Fine-grained mafic to intermediate volcanic rock; likely basaltic andesite/andesite, composition dominated by plagioclase with pyroxene and/or olivine

Vesicular basalt (weathered lava rock)

Basalt, a fine-grained mafic volcanic rock composed chiefly of plagioclase feldspar, pyroxene, and commonly olivine

Vesicular basalt (likely weathered volcanic scoria)

Basalt; chiefly plagioclase, clinopyroxene, olivine, and volcanic glass

Iron-stained quartz (likely milky quartz)

Quartz, SiO₂, with limonite/goethite iron-oxide staining

Weathered, rounded polymictic pebble (likely volcanic or metamorphic rock)

Indeterminate; possibly altered basalt, greenstone, or epidote-bearing metamorphic rock

Weathered basalt (possibly iron-stained volcanic rock)

Basalt; predominantly plagioclase, pyroxene, and possibly olivine, with iron-oxide staining

Galena

Galena (lead sulfide, PbS), likely with associated sulfide minerals

Pumice

Pumice, vesicular volcanic glass; typically silica-rich rhyolitic composition

Likely botryoidal calcite or aragonite specimen

Calcite (CaCO₃), possibly aragonite (CaCO₃)

Limestone

Calcium Carbonate (CaCO3)

Basalt

Basalt (Mafic volcanic rock)

Pumice

Pumice (a highly vesicular amorphous volcanic glass)

Biotite (Black Mica)

K(Mg,Fe)3AlSi3O10(OH,F)2

Polished basalt pebble (likely vesicular basalt)

Basalt; fine-grained mafic volcanic rock, principally plagioclase and pyroxene with possible olivine and iron oxides

Vesicular volcanic rock, likely scoria

Scoria; typically basaltic to andesitic volcanic rock composed mainly of plagioclase, pyroxene, and volcanic glass

Kyanite-bearing metamorphic rock

Blue kyanite (Al₂SiO₅), likely in mica- and garnet-rich schist

Milky quartz

Quartz (silicon dioxide, SiO₂)

Graphite-bearing schist (probable)

Graphite–quartz–mica schist; chiefly graphite (C), quartz (SiO₂), and mica

Quartz (Common or Milky)

Silicon Dioxide (SiO2)

Pyrite specimen

Pyrite, FeS₂ (iron disulfide)

Polished basalt cobble

Basalt; fine-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine

Pink Granite

Granite (Felsic Plutonic Igneous Rock)

Scoria (vesicular basalt)

Vesicular basalt; chiefly plagioclase, pyroxene, and iron-rich volcanic glass

Weathered jasper-rich ironstone

Brecciated jasper/chert with iron oxides and hydroxides (SiO₂ with hematite, goethite, and limonite)

Green Glass Slag

Amorphous Silicon Dioxide (SiO2) with metal oxide impurities

Iron-rich breccia (hematite–goethite rock)

Hematite (Fe₂O₃) and goethite (FeO(OH)) ironstone, likely ferruginous breccia

Iron-stained chert or siliceous sedimentary rock

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

Quartz-rich metamorphic rock, likely quartzite

Quartzite; predominantly crystalline SiO₂, with possible iron-oxide and dark mica/mineral inclusions

Likely iron sulfide specimen (pyrite or marcasite)

Pyrite, FeS₂; possibly marcasite, also FeS₂

Rhodonite

Rhodonite, manganese inosilicate — MnSiO₃; the specimen may include quartz, feldspar, and black manganese-oxide minerals in the matrix

Tumbled basalt or dark volcanic rock

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or iron oxides

Polished brown basalt or basaltic pebble

Basalt; fine-grained mafic volcanic rock, commonly composed of plagioclase, pyroxene, and olivine

Copper-bearing rock, likely bornite/chalcopyrite in iron-rich matrix

Chalcopyrite (CuFeS₂) and/or bornite (Cu₅FeS₄) in limonite/goethite matrix

Likely galena-bearing sulfide ore

Galena (lead sulfide, PbS), possibly with sphalerite and quartz/calcite gangue

Mica-rich pegmatite (likely muscovite-bearing)

Granitic pegmatite composed mainly of quartz, feldspar, and mica; mica is likely muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

Pumice

Pumice (Vesicular Felsic to Intermediate Volcanic Rock)

Basalt (Vesicular)

Extrusive igneous rock with vesicular texture

Pumice

Pumice (Highly vesicular volcanic glass)

Botryoidal Hematite (Iron Ore)

Iron(III) oxide (Fe2O3)

Limestone

Calcium Carbonate (CaCO3)

Iron-rich metamorphic rock, possibly micaceous schist

Biotite–quartz schist or iron-rich phyllite (tentative visual identification)

Pearl necklace

Pearl (biogenic calcium carbonate, chiefly aragonite; CaCO₃)