Metamorphic (Low Grade)

Chert (Common Opal variant)

Silicon Dioxide (SiO2)

Ferruginous Conglomerate

Conglomerate with Iron-Oxide Matrix (SiO2 + Fe2O3/FeO(OH))

Ironstone (likely Ferruginous Siltstone/Sandstone)

Ferruginous sedimentary rock (FeOx-rich clastic)

Ironstone Concretion

Siderite or Hematite-bonded Concretion

Ironstone Concretion (Iron-rich Mudstone)

Siderite / Geothite concretion (FeCO3 / FeO(OH))

Soapstone (Talc-Schist)

Steatite (composed primarily of Talc: Mg3Si4O10(OH)2)

Pink Opal (Common Opal)

Amorphous Hydrated Silica (SiO2·nH2O)

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Bloodstone (Heliotrope)

Silicon dioxide (SiO2) with Hematite inclusions

Biotite Schist

Biotite-rich Schist (K(Mg,Fe)3AlSi3O10(F,OH)2)

Amphibolite with Hornblende

Amphibole-rich Metamorphic Rock (Ca2(Mg,Fe)5Si8O22(OH)2)

Ironstone Concretion / Limonite Node

Ferruginous Sedimentary Rock (composed primarily of Limonite FeO(OH)·nH2O and Goethite)

Ferruginous Sandstone (with Iron Oxide staining)

Clastic Sedimentary Rock - Quartz Arenite/Wacke

Ferruginous Sandstone (Gozzan-like)

Ferruginous Sandstone (SiO2 with FeO(OH) inclusions)

Ferruginous Sandstone

Arenite with Iron-oxide cement (composed of Quartz and Limonite/Hematite)

Ironstone Nodule (Ironstone Concretion)

Siderite-rich Mudstone (FeCO3) or Limonite (FeO(OH)·nH2O)

Iron Gossan (Limonite/Goethite)

Hydrated Iron Oxides (FeO(OH)·nH2O) from oxidation zones

Tanzanite (Blue Zoisite)

Ca2Al3(SiO4)(Si2O7)O(OH) + (V) - Vanadium-bearing Zoisite

Mica Schist

Mica Schist (Composition typically contains Muscovite: KAl2(AlSi3O10)(OH)2 or Biotite: K(Mg,Fe)3AlSi3O10(OH)2 along with Quartz and Feldspar)

White Jade (Nephrite or Jadeite)

Nephrite (Ca2(Mg, Fe)5Si8O22(OH)2) or Jadeite (NaAlSi2O6)

Garnet Schist

Almandine-Mica Schist

Petrified Wood

Silicified Wood (SiO2)

Garnet in Matrix (likely Almandine in Quartz/Mica Schist)

Almandine Garnet (Fe3Al2(SiO4)3) in Quartz-Feldspar host rock

Biotite Schist

Biotite Gneiss/Schist (approximate formula K(Mg,Fe)3AlSi3O10(OH)2)

Quartz Mica Schist

Mica-Quartz Schist (Chemical: SiO2 + KAl2(AlSi3O10)(OH)2)

Peridotite (with Olivine and Pyroxene)

Ultramafic Magmatic Rock (Primary minerals: (Mg, Fe)2SiO4 and (Ca, Mg, Fe)2Si2O6)

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

Lepidolite

Lepidolite (K(Li,Al)3(Al,Si,Rb)4O10(F,OH)2)

Ruby in Quartz with Tourmaline

Corundum (Al2O3) in Silicon Dioxide (SiO2) with Schorl

Gneiss

Gneiss

Mica Schist

Mica Schist (primarily Muscovite and Biotite)

Anthracite Coal

Anthracite (Metamorphosed Carbon)

Gneiss

Gneiss (Metamorphic rock)

Fuchsite Schist

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

Quartzite Cobble

Quartzite (SiO2)

Turquoise (Dyed Howlite/Magnesite)

CuAl6(PO4)4(OH)8·4H2O (Natural Turquoise) or Ca2B5SiO9(OH)5 (Howlite)

Pearl

Biogenic Calcium Carbonate (Aragonite and Conchiolin), CaCO3

Gold-bearing Quartz Ore

Auriferous Quartz (SiO2 with Au)

Chrysocolla on Quartz/Rhyolite matrix

Hydrated copper phyllosilicate mineral: (Cu,Al)2H2Si2O5(OH)4·nH2O

Turquoise

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

Fire Agate (Rough)

Silicon Dioxide (SiO2) - Variety of Chalcedony