Industrial By Product

Limestone

Calcium Carbonate (CaCO3)

Pumice

Pumice (a highly vesicular extrusive igneous rock)

Blue Calcite

Calcium Carbonate (CaCO3)

Polished magnetite-rich rock, likely magnetite-bearing schist or ironstone

Magnetite (Fe₃O₄) in a foliated silicate matrix; exact identification requires testing

Basalt pebble

Fine- to medium-grained mafic volcanic rock, chiefly plagioclase and pyroxene with possible olivine and iron oxides

Weathered granite or granitic gneiss slab

Granitic rock, chiefly quartz, feldspar, and mica; exact identification is uncertain from the photograph

Weathered granite or granitic gneiss

Quartz–feldspar–mica granitoid; possibly gneiss if the visible layering is tectonic

Tumbled pink feldspar-rich stone

Likely microcline feldspar (KAlSi₃O₈), possibly granite or quartz-feldspar pegmatite

Likely weathered basalt or vesicular volcanic rock

Basalt, composed mainly of plagioclase feldspar, pyroxene, and minor olivine/iron oxides

Tumbled serpentine

Serpentinite; chiefly antigorite, lizardite, and/or chrysotile serpentine-group minerals

Chrysotile Asbestos

Mg3Si2O5(OH)4

Copper-bearing porphyritic rock (likely bornite/chalcopyrite ore)

Altered porphyritic volcanic rock with copper sulfides, chiefly bornite (Cu₅FeS₄) and/or chalcopyrite (CuFeS₂)

Weathered foliated metamorphic rock, likely schist or phyllite

Micaceous quartz–feldspar schist/phyllite; exact identification requires petrographic or chemical testing

Opalite

Synthetic Opalized Glass (SiO2 + additives)

Fluorite (Rainbow Fluorite)

Calcium Fluoride (CaF2)

Slate

Slate (Foliated Metamorphic Rock)

Galena

Galena (lead sulfide, PbS)

Popcorn

Zea mays everta (P. Wilson) (Botanical name for the corn variety)

Quartz Geode or Druzy Quartz in Host Rock

Silicon Dioxide (SiO2)

Hematite (Concretion)

Iron(III) oxide (Fe2O3)

Dragon Vein Agate

Chalcedony (Quartz) - SiO2

Weathered basalt or andesitic volcanic rock

Porphyritic basalt–andesite; likely plagioclase and pyroxene with iron-oxide alteration

Milky quartz-bearing metamorphic rock, likely quartzite

Quartzite, composed predominantly of quartz (SiO₂), possibly with mica and feldspar

Iron-stained quartz-rich rock, possibly brecciated quartzite or rhyolite

Indeterminate quartz–feldspar rock with iron-oxide staining (SiO₂-rich; possible hematite/goethite)

Iridescent bismuth crystal

Bismuth (Bi), commonly laboratory-grown and oxide-coated

Weathered vesicular volcanic rock (likely pumice/tuff)

Porous volcanic pyroclastic rock, probably pumiceous tuff; exact identification requires testing

Tumbled feldspar-rich rock, likely pink-orange microcline or granite fragment

K-feldspar (microcline/orthoclase), approximately KAlSi₃O₈; exact identification requires testing

Dark basalt (likely porphyritic basalt)

Basalt, composed mainly of plagioclase feldspar, pyroxene, and commonly olivine

Weathered volcanic rock, likely basalt

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine or alteration minerals

Weathered iron-rich rock, possibly laterite or limonite-bearing sandstone

Iron oxides/hydroxides, chiefly limonite/goethite (FeO(OH)·nH₂O), with a probable silicate or clay matrix

Weathered gneiss

Banded gneiss, commonly composed of quartz, feldspar, and mica

Hematite

Hematite (Fe2O3)

Weathered granite or granitic gneiss fragment

Quartz–feldspar–mica aggregate; likely granite (possibly gneiss)

Weathered, vesicular volcanic rock (likely pumice/scoria)

Pumice or scoriaceous basalt; composition likely volcanic glass with feldspar, pyroxene, and minor iron oxides

Coarse granite (likely weathered biotite granite)

Granite; quartz + feldspar + biotite/hornblende, approximate composition 20–60% quartz and abundant K-feldspar/plagioclase

Black tourmaline (schorl), probable

Schorl tourmaline, NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Black tourmaline pendant

Schorl tourmaline, NaFe3Al6(BO3)3Si6O18(OH)4

Pumice

Vesicular volcanic glass (primarily Alumino-silicates)

Quartzite

Metamorphosed Quartz Sandstone

Pumice

Pumice

Chert (Flint/Jasper variety)

Silicon Dioxide (SiO2)

Basalt

Basalt (composition of Plagioclase feldspar, Pyroxene, and Olivine)