Synthetic Material (Not A Rock Or Mineral)

Aventurine (Green)

Aventurine Quartz (SiO2 + Fuchsite inclusions)

Quartz Pebble (Water-worn)

Silicon Dioxide (SiO2)

Petrified Wood

Silicified wood (Quartz, SiO2)

Mookaite Jasper

Siliceous sedimentary rock (variety of Jasper/Chert)

Quartzite

Quartzite (primarily SiO2)

Chert (or Flint)

Chert (a cryptocrystalline variety of quartz, SiO2)

Limonite (Iron Stone Concretion)

Limonite (Hydrous Iron Oxide) - FeO(OH)·nH2O

Amethyst

Amethyst (Silicon Dioxide, SiO2)

Milky Quartz with Mineral Inclusions

Silicon Dioxide (SiO2)

Peridot (Olivine)

Olivine ((Mg, Fe)2SiO4)

Quartz / Milky Quartz

Silicon Dioxide (SiO2)

Petrified Wood

Silicified Wood (primarily SiO2)

Quartz Vein in Schist

Quartz (SiO2) in Mica Schist

Quartz-veined Basalt

Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein

Chert (White Chert / Flint)

Microcrystalline or Cryptocrystalline Quartz (SiO2)

Basalt with Quartz Veining

Basalt (Mafic Extrusive Igneous Rock) with SiO2 (Silicon Dioxide) veins

Glauconitic Sandstone (or Greensand)

Glauconitic Siliciclastic Rock (Containing (K,Na)(Fe,Al,Mg)2(Si,Al)4O10(OH)2)

Quartz-Veined Mudstone

Argillaceous Mudstone with Quartz Veining

Quartz Pebble

Silicon Dioxide (SiO2)

Nephrite Jade

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2)

Black Limestone with Calcite Veining

Bituminous Limestone (CaCO3 with Organic Carbon inclusions)

Coral Fossil (Scleractinia)

Scleractinia (Order), primarily CaCO3 (Aragonite or Calcite)

Red Jasper

Silicon Dioxide (SiO2) with iron oxide inclusions

Petrified Wood

Silicified Wood (SiO2)

Petrified Wood

Silicified wood (Quartz, Chalcedony, or Opal)

Fluorite

Calcium Fluoride (CaF2)

Greenschist

Greenschist (Actinolite-Chlorite Schist)

Granite

Granite (Mainly Quartz, Alkali Feldspar, and Plagioclase)

Clear Quartz

Silicon dioxide (SiO2)

Lapis Lazuli (Tumbled)

Lazurite-dominated contact metamorphic rock

Lapis Lazuli

Na8[Al6Si6O24]Sn (Lazurite-rich metamorphic rock)

Tiger's Eye (with Blue Tiger's Eye / Hawk's Eye)

Pseudomorph of Quartz after Crocidolite (SiO2 with inclusions)

Milky Quartz with inclusions

Silicon Dioxide (SiO2)

Eclogite

Eclogite (Omphacite + Pyrope)

Turquoise, Pearl, and Coral Necklace

CuAl6(PO4)4(OH)8·4H2O (Turquoise) / CaCO3 (Pearl and Coral)

Petrified Wood

Silicified Wood (primarily SiO2)

Travertine (used in construction, not a 'specimen' in situ)

Travertine

Quartz Geode (with possible Manganese or Goethite coating)

Silicon Dioxide (SiO2)

Turquoise

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

Blue Quartzite (Aventurine variety)

Silicon Dioxide (SiO2) with inclusions of Dumortierite or Magnesio-riebeckite

Bauxite

Bauxite (Al2O3·nH2O)

Limonite-stained Quartz

Silicon Dioxide (SiO2) with Iron Oxide/Hydroxide (FeO(OH)·nH2O) staining