Mineral (Primary Constituent)

Citrine

Citrine (Silicon Dioxide - SiO2)

Cavansite

Cavansite (Ca(VO)Si4O10·4H2O)

Amazonite

Potassium feldspar (Microcline), K(AlSi3O8)

Kambaba Jasper

Stromatolite (Fossilized Algae within Microcrystalline Quartz)

Ocean Jasper (Orbicular Jasper)

Silicon Dioxide (SiO2) with iron and other impurities

Amethyst (Tumbled/Polished)

Silicon Dioxide (SiO2) with iron impurities

Amethyst

Silicon dioxide (SiO2) containing traces of iron and manganese

Limonite (Iron-rich Siltstone / Sandstone base)

Hydrous ferric oxide mixture (FeO(OH)·nH2O)

Smoky Quartz

Silicon Dioxide (SiO2)

Biotite Schist

Biotite Schist

Quartz Geode

Silicon Dioxide (SiO2) in a concretionary structure

Tree Agate (or Moss Agate)

Dendritic Agate (Silicon Dioxide - SiO2)

Sapphirine in Magnesian Schist

Sapphirine: (Mg,Al)8(Al,Si)6O20

Moonstone

Orthoclase Feldspar (KAlSi3O8) or Albite mixtures

Precious Opal

Hydrated Silica (SiO2·nH2O)

Fluorite

Calcium Fluoride (CaF2)

Tiger's Eye

Pseudomorph of Quartz after Crocidolite (SiO2 with Iron Oxide inclusions)

Obsidian

Volcanic Glass (SiO2 - Silicon Dioxide with impurities)

Granite

Granite (a common rock type, not a single mineral; composed primarily of Quartz, Feldspar (Orthoclase and Plagioclase), and Mica (Biotite and/or Muscovite) and/or Amphibole)

Obsidian

Volcanic glass (SiO2 - Silicon dioxide predominant composition)

Fluorite

Fluorite (Calcium Fluoride, CaF2)

Sandstone

Sandstone (clastic sedimentary rock, composed predominantly of sand-sized minerals or rock fragments)

Selenite

Gypsum (CaSO4·2H2O), specifically the crystalline variety Selenite

Geode (Unopened)

Vug or Geode (primarily Silicon Dioxide, SiO2)

Fire Agate

Agate (Variety of Chalcedony), SiO2 (Silicon Dioxide)

Pyrite

Iron Disulfide (FeS2)

Ptygmatic Migmatite

Migmatite (consisting of Neosome and Paleosome fractions)

Smoky Quartz with Iron Inclusions

Silicon Dioxide (SiO2)

Epidote

{Ca2}{Al2Fe3+}(Si2O7)(SiO4)O(OH)

Amethyst

Amethyst (Silicon Dioxide - SiO2 with iron impurities)

Emerald

Beryl (Be3Al2(SiO3)6) with Chromium/Vanadium impurities

Spessartine Garnet

Manganese aluminum silicate (Mn2+3Al2(SiO4)3)

Chrysocolla Chalcedony

Hydrated Copper Phyllosilicate (Cu,Al)2H2Si2O5(OH)4 + SiO2

Blue Calcite

Calcium Carbonate (CaCO3)

Black Tourmaline in Quartz Matrix

Schorl (NaFe3Al6(BO3)3Si6O18(OH)4) with Quartz (SiO2)

Fuchsite

Chromium-rich Muscovite (K(Al,Cr)2(AlSi3O10)(OH)2)

Larimar

Pectolite [NaCa2Si3O8(OH)] with copper substitution

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)

Staurolite (Fairy Cross)

Staurolite (Fe2+2Al9Si4O23(OH))

Quartz Druzy on Matrix (likely Agate or Jasper)

Silicon Dioxide (SiO2) with various mineral inclusions

Moss Agate

Chalcedony (SiO2) with dendritic inclusions of Manganese or Iron oxide

Epidosite (Epidote-rich rock)

Epidotalite (primarily Ca2(Al2Fe3+)(SiO4)(Si2O7)O(OH))