Mineral Like Biological Tissue

Druzy Agate (Star-cut Geode Slice)

Silicon Dioxide (SiO2) - Microcrystalline and Macrocrystalline Quartz

Purple Agate (Dyed Chalcedony)

SiO2 (Silicon Dioxide) with organic dyes

Quartz (River Pebble)

Silicon Dioxide (SiO2)

Azurite with Malachite and Limonite

Azurite Cu3(CO3)2(OH)2 / Malachite Cu2CO3(OH)2

Granite

Phaneritic Felsic Igneous Rock

Quartz Geode

Crystalline Silicon Dioxide (SiO2) within a nodule

Sandstone (Red Sandstone / River Stone)

Arenite (composed primarily of Quartz, SiO2, with Iron Oxide cementation)

Ruby in Matrix

Corundum (Al2O3)

Nuummite

Nuummite (Orthorhombic amphiboles: Anthophyllite and Gedrite)

Amazonite

Potassium Feldspar (KAlSi3O8)

Manganese Ore (Psilomelane/Pyrolusite)

Psilomelane ((Ba,H2O)2Mn5O10) and Pyrolusite (MnO2)

Moss Agate

Silicon Dioxide (SiO2) with inclusions of Manganese or Iron oxides

Olivine (Peridot)

Olivine Group (Mg,Fe)2SiO4

Chert (Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Native Gold Nuggets

Native Gold (Au)

Amber and Citrine Quartz

Succinite (Amber) and Silicon Dioxide (SiO2 / Citrine)

Ferruginous Quartz

Silicon Dioxide (SiO2) with Iron Oxide (Fe2O3) inclusions

Quartz Druzy on Matrix (with Copper Mineralization)

Silicon Dioxide (SiO2) with Chrysocolla (Cu2-xAlx(H2-xSi2O5)(OH)4·n H2O)

Quartz (Milky/Iron-stained)

Silicon Dioxide (SiO2)

Quartz

Silicon Dioxide (SiO2)

Kyanite in Quartz

Al2SiO5 in SiO2

Sandstone (Ferruginous)

Arenite (composed primarily of SiO2 with Fe2O3 cement)

Green Aventurine

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

Sandstone (likely Quartzose Sandstone)

Arenite (primarily SiO2)

Schist

Mica Schist

Hypersthene

Hypersthene (formula: (Mg,Fe)SiO3)

Sandstone or Limestone

Arenite or Calcareous Sedimentary Rock

Sandstone (likely Quartz Sandstone)

Arenite (composed primarily of SiO2)

Pyrite (Fool's Gold)

Iron Disulfide (FeS2)

Sandstone (with Iron Staining)

Clastic sedimentary rock (primarily SiO2 with Fe2O3 staining)

Kyawthuite

Kyawthuite (Bi3+Sb5+O4)

Pyrite and Fluorite on Quartz (Matrix Specimen)

Iron Disulfide (FeS2) and Calcium Fluoride (CaF2) with Silicon Dioxide (SiO2)

Tourmalinated Quartz

Silicon Dioxide (SiO2) with Schorl inclusions (NaFe2+3Al6(BO3)3Si6O18(OH)4)

Sandstone or Mudstone with Iron Staining

Ferruginous Sandstone/Mudstone

Orthoclase Feldspar (Twinning Specimen)

Orthoclase (KAlSi3O8)

Tiger's Eye

Tiger's eye (Pseudomorph of Quartz after Crocidolite), SiO2

Sandstone (likely River-tumbled Picture Sandstone)

Arenite (predominantly SiO2 with iron oxide impurities)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Olivine (Peridot)

Magnesium Iron Silicate (Mg, Fe)2SiO4

Sandstone (Pebble)

Arenite (primarily SiO2)

Limonite with Opal infusion

FeO(OH)·nH2O (Limonite) / SiO2·nH2O (Opal)

Sandstone (Quartzose Sandstone)

Clastic sedimentary rock (primarily SiO2)