Mineralogical Specimen

Clear Quartz

SiO2 (Silicon Dioxide)

Fossilized Bone Chunk

Permineralized Vertebrate Bone (indeterminant)

Brachiopod Fossil in Limestone

Phylum Brachiopoda embedded in sedimentary rock

Fossilized Oyster in Flint

Gryphaea or Exogyra embedded in SiO2 (Flint/Chert)

Quartz Geode with Calcite

Silicon Dioxide (SiO2) and Calcium Carbonate (CaCO3)

Agate

Silicon dioxide (SiO2)

Orbicular granite (likely weathered granitic rock with feldspar phenocryst)

Granite; chiefly quartz, K-feldspar, plagioclase, and biotite/hornblende

Biotite-rich schist with garnet-like inclusion

Mica schist; predominantly muscovite/biotite mica, quartz, and feldspar, with a possible garnet or weathered mafic fragment

Fossilized oyster shell

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

Chert (Carnelian/Jasper variety)

Microcrystalline Quartz (SiO2)

Aventurine Quartz

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

Granite or Granitic Gneiss River Rock

Granite

Amethyst (Super Seven / Melody's Stone Variety)

Silicon Dioxide (SiO2) with trace impurities including Iron

Granite Pebble

Felsic Intrusive Igneous Rock

Sulfur-bearing Limestone (Solfatara Specimen)

Sulfur-rich Bio-limestone (Calcium Carbonate with Native Sulfur, S8)

Chalcedony (Agate/Common Opal blend)

Microcrystalline Quartz (SiO2)

Granite (Orthoclase rich)

Granite (composed primarily of Quartz and Potassium Feldspar KAlSi3O8)

Granite (likely weathered granitic rock)

Granite; primarily quartz (SiO₂), feldspar, and mica/amphibole

Iron-rich quartzite or weathered ironstone

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

Unidentified gray-green rock specimen

Possibly banded gneiss or another foliated metamorphic rock; identification is uncertain from the image

Labradorite (Tumbled)

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

Sparkling Druzy Quartz on Matrix

Silicon Dioxide (SiO2) with iron oxide inclusions

Dark rock specimen (possibly slate or shale)

Unidentified fine-grained rock; slate is foliated metamorphosed shale, while shale is sedimentary mudrock

Coarse-grained granite or granitic gneiss

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

Quartz crystal

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

Small unidentified mineral specimen

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

Quartz Druse on Basalt Matrix

Silicon Dioxide (SiO2)

Banded Agate (with Quartz Geode Center)

Silicon Dioxide (SiO2)

Jasper

Silicon Dioxide (Microcrystalline Quartz), SiO2

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

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

Quartz Geode

Silicon Dioxide (SiO2)

Clear Quartz (Faceted)

Silicon dioxide (SiO2)

Diamond

Carbon (C)

Diamond

Carbon (C)

Diamond inlaid in Jewelry

Carbon (C)

Raw black tourmaline (likely schorl)

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

Metallic Ornament / Jewelry

N/A - This is an artificial object, not a geological specimen.

Copper-stained quartz/igneous rock specimen

Quartz (SiO₂), with secondary copper minerals; host likely altered volcanic rock

Unable to identify - Image contains non-geological items

Quartz with Spessartine Garnet and Biotite

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

Quartz with Mica/Schist inclusion

Silicon Dioxide (SiO2) with Phyllosilicates

Mica Schist with Garnet

Almandine-Mica Schist