Mineral (Evaporite)

Gossan (Iron Hat)

Limonitic Gossan (predominantly FeO(OH)·nH2O)

Granite (Thin Section)

Granite (Felsic Plutonic Rock)

Biotite Schist (likely)

Biotite Schist (rock), Biotite (mineral)

Fluorite

Calcium Fluoride (CaF2)

Schist with Quartz Veins

Schist with Quartz (SiO2)

Milky Quartz (with Chlorite/Mineral Inclusions)

Silicon Dioxide (SiO2)

Native Copper

Native Copper (Cu)

Banded Gneiss (with possible weathered sulfide or iron staining)

Gneiss, potentially with iron oxide/hydroxide staining (e.g., limonite) or weathered sulfides

Quartz Pebble (with Iron Inclusions)

Silicon Dioxide (SiO2)

Fluorite Geode

Calcium Fluoride (CaF2)

Chalcedony (Botryoidal Agate vein)

Chalcedony (Microcrystalline Quartz) - SiO2

White Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Milky Quartz Pebble

Quartz (Silicon Dioxide, SiO2)

Sandstone Concretion (Omar or Nut Rock)

Sedimentary Concretion (specifically an 'Omarolluk' or Omar)

Milky Quartz with Iron Inclusions

Quartz (Silicon Dioxide, SiO2)

Quartz (Milky Quartz)

Silicon Dioxide (SiO2)

Green Fluorite

Calcium Fluoride (CaF2)

Quartz (Granular Milky Quartz fragment)

Silicon Dioxide (SiO2)

Feldspar (Orthoclase)

Orthoclase Feldspar (KAlSi3O8)

Hematite (Concretion)

Iron(III) oxide (Fe2O3)

Orthoclase Feldspar (Twinning Specimen)

Orthoclase (KAlSi3O8)

Fluorite (Purple Fluorite in Matrix)

Fluorite (Calcium Fluoride, CaF2)

Gneiss (specifically a Granitic Gneiss specimen)

Gneiss (high-grade metamorphic rock primarily composed of Quartz, Feldspar, and Biotite/Amphibole)

Heat-Treated Amethyst (Commercial Citrine)

Silicon Dioxide (SiO2) - Macro-crystalline Quartz

Banded Gneiss

Gneiss (High-grade Regional Metamorphic Rock)

Travertine (often colloquially called Tufa)

Chemical Sedimentary Calcium Carbonate (CaCO3)

Schist

Schist (Crystalline metamorphic rock)

Rutilated Quartz

Silicon Dioxide (SiO2) with inclusions of Titanium Dioxide (TiO2)

Red Sandstone

Arenite (Fe2O3 enriched)

Turquoise

Turquoise, CuAl6(PO4)4(OH)8·4H2O

Quartz Vein

Silicon Dioxide (SiO2)

Sandstone (Ferruginous)

Arenite with Hematite cement (SiO2 + Fe2O3)

Jasper

Jasper (Silicon Dioxide, SiO2)

Sandstone (Ferruginous)

Arenite (primarily SiO2 with Fe2O3 staining)

Lepidolite

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

Sandstone

Arenite

Limonite with Galena

FeO(OH)·nH2O (Limonite) and PbS (Galena)

Gold-bearing Quartz with Iron Oxides

Quartz (SiO2) with Limonite/Goethite (FeO(OH)) and Pyrite (FeS2)

Sandstone

Arenite (SiO2 based typically)

Turquoise

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

Turquoise

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

Obsidian

Volcanic glass (SiO2-rich extrusive igneous rock)