Sedimentary (Secondary Mineral) Within Igneous

Blue Calcite

Calcium Carbonate (CaCO3)

Chalcedony (Moonstone variant or White Agate)

Silicon Dioxide (SiO₂)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Sedimentary/Volcanic cavity

Quartz Geode

Silicon Dioxide (SiO2) in sedimentary host rock

Band Agate / Jasper

Silicon Dioxide (SiO2) - Microcrystalline Quartz

Quartz Geode

Silicon Dioxide (SiO2)

Quartz-veined Siltstone

Siltstone with Quartz (SiO2) veins

Kaolinite (Chalky Clay)

Kaolinite (Al2Si2O5(OH)4)

Ferruginous Quartz

Silicon Dioxide with Hematite/Limonite inclusions (SiO2 + Fe2O3)

Sandstone with Concretions / Liesegang Rings

Arenite with iron oxide banding

Chalcedony (Yellow Agate)

Cryptocrystalline Quartz (SiO2)

Milky Quartz with Chlorite / Mica inclusions

Silicon Dioxide (SiO2) with phyllosilicate inclusions

Honey Calcite

Calcium Carbonate (CaCO3)

Quartz (Citrine or Iron-Stained variety)

Silicon Dioxide (SiO2)

Green Calcite

Calcium Carbonate (CaCO3)

Blue Celestite (with Galena)

Strontium sulfate (SrSO4) and Lead sulfide (PbS)

Quartz Geode

Silicon Dioxide (SiO2)

Chert Pebble with Quartz Veins

Microcrystalline Quartz (SiO2)

Weathered vesicular volcanic rock, likely pumiceous andesite or rhyolite

Pumiceous intermediate-to-felsic volcanic rock; commonly composed of plagioclase, quartz, alkali feldspar, and volcanic glass, with possible iron-oxide staining

Ferruginous Quartz

Silicon Dioxide with Iron Oxide inclusions (SiO2 + Fe2O3)

Amethyst Cluster

Silicon dioxide (Quartz variety, $SiO_2$)

Prehnite

Prehnite (Ca2Al(AlSi3O10)(OH)2)

Prehnite

Prehnite (Ca2Al2Si3O10(OH)2)

Quartz Geode

Silicon Dioxide (SiO2) in a Secondary Formation

Turquoise

Hydrated phosphate of copper and aluminium: CuAl6(PO4)4(OH)8·4H2O

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

Lepidolite

K(Li,Al)3(Al,Si)4O10(F,OH)2 (Lithium-bearing phyllosilicate)

Turquoise

Turquoise (CuAl6(PO4)4(OH)8·4H2O)

Turquoise

Turquoise, CuAl6(PO4)4(OH)8·4H2O

Turquoise

Hydrated phosphate of copper and aluminium (CuAl6(PO4)4(OH)8·4H2O)

Granite Pebble with Quartz Vein

Granite (Plutonic Igneous Rock) with Quartz (SiO2)

Limestone with Calcite Veins

Calcium Carbonate (CaCO3)

Yellow Ocherous Siltstone (Limonitic Shale)

Limonitic Siltstone / Goethite-rich Sedimentary Rock

Vesicular basalt (possibly weathered scoria)

Basaltic volcanic rock; chiefly plagioclase, clinopyroxene, and Fe–Mg oxides, with vesicles from trapped gas

Green Calcite

Calcium Carbonate (CaCO3)

Likely weathered blue-gray basalt

Basalt, a fine-grained mafic volcanic rock; commonly plagioclase + pyroxene ± olivine and iron oxides

Basalt with Plagioclase or Quartz Inclusion

Melanocratic Basalt with Porphyritic Inclusion

Banded Iron Formation (BIF) / Banded Sandstone Nodule

Hematite-rich Sandstone / Ferruginous Chert

Chalcedony (Agate/Carnelian variant)

Silicon Dioxide (SiO2)

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O (Hydrous phosphate of copper and aluminium)

Porphyritic basalt (likely amygdaloidal basalt)

Basalt, a mafic volcanic rock; composition typically plagioclase + pyroxene, with possible olivine and vesicle-filling minerals

Quartz Geode

Crystalline Quartz (Silicon Dioxide, SiO2)