Mineralological Specimen

Chalcedony (Agate/Common Opal blend)

Microcrystalline Quartz (SiO2)

Granite (Orthoclase rich)

Granite (composed primarily of Quartz and Potassium Feldspar KAlSi3O8)

Pink-and-gray quartz-rich pegmatite, possibly rose quartz with feldspar

Quartz (SiO₂) with K-feldspar/plagioclase; likely pegmatitic granite

Amethyst quartz crystal

Quartz, silicon dioxide (SiO₂), purple variety amethyst

Fossilized oyster shell

Bivalve mollusk fossil, likely Gryphaea or Exogyra; calcite (CaCO₃) shell material

Aventurine Quartz

Silicon Dioxide with Fuchsite inclusions (SiO2 + K(Al,Cr)2AlSi3O10(OH)2)

Raw turquoise

Turquoise, hydrated copper aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O

Granite Pebble

Felsic Intrusive Igneous Rock

Iron-rich quartzite or weathered ironstone

Quartzite dominated by quartz (SiO₂), with iron oxides/hydroxides such as hematite and goethite

Quartz Druse on Basalt Matrix

Silicon Dioxide (SiO2)

Banded Agate (with Quartz Geode Center)

Silicon Dioxide (SiO2)

Quartz crystal

Quartz (SiO₂), likely milky or iron-stained quartz

Granite or Granitic Gneiss River Rock

Granite

Amethyst (Super Seven / Melody's Stone Variety)

Silicon Dioxide (SiO2) with trace impurities including Iron

Jasper

Silicon Dioxide (Microcrystalline Quartz), SiO2

Labradorite (Tumbled)

Plagioclase Feldspar (Na,Ca)(Al,Si)4O8

Sparkling Druzy Quartz on Matrix

Silicon Dioxide (SiO2) with iron oxide inclusions

Coarse-grained granite or granitic gneiss

Granite; chiefly quartz, potassium feldspar, plagioclase, and biotite/hornblende. The pronounced streaking may indicate gneissic deformation.

Iron-rich hematite specimen

Hematite (α-Fe₂O₃), likely with limonite/goethite and host-rock impurities

Quartz with Mica/Schist inclusion

Silicon Dioxide (SiO2) with Phyllosilicates

Mica Schist with Garnet

Almandine-Mica Schist

Fossiliferous Limestone

Bioclastic Limestone (CaCO3)

Chert (Jasper)

Microcrystalline Quartz (SiO2)

Likely basalt or another dark, coarse-grained igneous rock

Possibly olivine-bearing basalt (plagioclase, pyroxene, and possibly olivine); identification is uncertain from the photo

Porphyritic volcanic rock, likely andesite or rhyolite

Porphyritic andesite–rhyolite; chiefly plagioclase, quartz, and altered ferromagnesian minerals in a fine groundmass

Possible garnet crystal

Likely almandine garnet, Fe₃Al₂(SiO₄)₃; identification is uncertain from this small image

Likely raw quartz-bearing stone, possibly greenish quartz or calcite

Uncertain from photograph; possible quartz (SiO₂) or calcite (CaCO₃)

Raw black tourmaline (likely schorl)

Schorl, sodium–iron tourmaline; approximately NaFe²⁺₃Al₆(BO₃)₃Si₆O₁₈(OH)₄

Small unidentified mineral specimen

Indeterminate from image; possibly a quartz-family crystal or sulfide mineral

Quartz with Spessartine Garnet and Biotite

SiO2 (Quartz) with Mn3Al2(SiO4)3 (Spessartine)

Rock specimen shown in a classroom identification activity

Undetermined; the pictured specimen may be a fine-grained, pinkish rock, but the image does not provide enough detail for a reliable identification

Quartz Geode

Silicon Dioxide (SiO2)

Conglomerate

Conglomeratic Sandstone

Granite with Tourmaline or Biotite

Phaneritic Igneous Rock (Granoid)

Banded Sandstone

Quartz Arenite (with iron oxide banding)

Porphyritic Andesite

Andesite (Porphyritic texture)

Quartz Geode with Goethite/Hematite

Silicon Dioxide (SiO2) with Iron Oxides

Smoky Quartz (Herkimer-style)

Silicon Dioxide (SiO2)

Muscovite Schist

Metamorphic rock primarily composed of quartz and muscovite mica

Blue Obsidian

Volcanic Glass (SiO2 with inclusions)

Clear Quartz (Faceted)

Silicon dioxide (SiO2)

Diamond

Carbon (C)