Mineral Specimen

Schist (Greenschist / Mica Schist)

Schist (variable mineral composition, commonly containing quartz, feldspar, mica, chlorite)

Quartz (Field Specimen)

Silicon Dioxide (SiO2)

Milky Quartz with Mica

Silicon Dioxide (SiO2) with Muscovite or Biotite inclusions

Quartz Vein in Matrix

Silicon Dioxide (SiO2) within Rhyolitic or Granitic Matrix

Chrysocolla in Quartz

Hydrated copper phyllosilicate with silicon dioxide (Cu2-xAlx(H2-xSi2O5)(OH)4·nH2O + SiO2)

Banded Agate Geode

Silicon Dioxide (SiO2)

Jasper (Iron-stained Quartzite/Chert)

Silicon Dioxide (SiO2) with iron oxide inclusions

Clear/White Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Quartz / Calcite Vein Rock

Silicon Dioxide (SiO2) or Calcium Carbonate (CaCO3)

Jasper-Agate

Silicon Dioxide (SiO2)

Brown Quartz (Jasper or Chert)

Silicon Dioxide (SiO2)

Milky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Granite

Intrusive Igneous Rock

Muscovite Schist

Metamorphic rock primarily composed of quartz and muscovite mica

Granite

Intrusive Igneous Rock

Agate

Silicon dioxide (SiO2)

Raw black tourmaline (likely schorl)

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

Quartz (Milky/Clear variety)

Silicon Dioxide (SiO2)

Gossan / Iron-Rich Weathered Rock

Hydrated Iron Oxides / Limonite / Goethite

Clear Quartz Crystal Cluster

Silicon Dioxide (SiO2)

Granite Pebble

Granite

Quartz with Mica (Muscovite or Biotite)

Silicon Dioxide (SiO2) with Phyllosilicates

Green Quartz (Prasiolite/Adventurine)

Silicon Dioxide with inclusions (SiO2)

Quartz with Epidote

Silicon Dioxide (SiO2) with Calcium Aluminum Iron Silicate [Ca2(Al,Fe)3(SiO4)3(OH)]

Amethyst on Agate

Crystalline Quartz (SiO2) with trace Iron (Fe3+)

Quartz

Silicon dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Pyrite in Matrix

Iron Sulfide (FeS2)

Agate Geode

Cryptocrystalline Quartz (SiO2) with Chalcedony banding

Amethyst

Silicon Dioxide (SiO2) with iron impurities

Milky Quartz with Mica and Pyrite

Quartz (SiO2) with Muscovite (KAl2(AlSi3O10)(OH)2) and Pyrite (FeS2)

Limonite (Ironstone) pseudomorph

Limonite (Hydrous ferric oxide), FeO(OH)·nH2O

Schist

Mica Schist

Calcite specimen

Calcite (calcium carbonate, CaCO₃), likely botryoidal or drusy calcite

Quartz / Common Opal Transition

Silicon Dioxide (SiO2)

Quartz Geode

Silicon Dioxide (SiO2)

Diamond

Carbon (C)

Native Copper with Malachite/Oxide Coating

Native Copper (Cu)

Quartz-Veined Slate or Greenstone

Metamorphic rock with quartz vein (SiO2)

Quartz Pebble

Silicon Dioxide (SiO2)

K-Feldspar Granite Fragment

Granite (Alkali Feldspar-rich)

Quartz Geode

Silicon Dioxide (SiO2)