Opaque Minerals
- Name of mineral [chemical composition]
- Colours
- # Mohs' scale of hardness; Type of crystals
- Uses
- Acanthite (See: Argentite)
- Antimony [Native antimony]
- Silver-white
- # 3-3.5; Trigonal
- Research, collections
- Argentite [Silver sulfide]
- Lead-grey
- # 2-2.5; Cubic
- Source of silver
- Arsenic [Native arsenic]
- White, grey
- # 3-3.5; Trigonal
- No industrial use
- Arsenopyrite [Iron arsenic sulfide]
- Tin-white, steel-grey
- # 5.5-6; Monoclinic
- Source of arsenic, source of gold, silver, tin, cobalt as by-products
- Bismuthite [Bismuth sulfide]
- Lead-grey, tin-white, dull yellow
- # 2; Orthorhombic
- Source of bismuth
- Bornite [Copper iron sulfide]
- Red, bronze
- # 3; Cubic
- Source of copper
- Bournonite [Lead copper antimony sulfide]
- Grey, iron-black
- # 2.5-3; Orthorhombic
- Minor source of lead, copper, antimony
- Chalcocite [Copper sulfide]
- Lead-grey, black with blue reflections
- # 2.5-3; Orthorhomic
- Source of copper
- Chalcopyrite [Copper iron sulfide]
- Brass-yellow with green tones
- # 3.5-4; Tetragonal
- Source of copper; source of gold and silver as by-products
- Chromite [Iron chromate]
- Grey, grey-black, steel
- # 5.5; Monoclinic
- Minor source of copper
- Cobaltite [Cobalt sulfarsenide]
- White-grey with rose
- # 5.5; Orthorhombic
- Research, collections
- Columbite [Niobium iron oxide]
- Iron-black, black-brown
- # 6; Orthorhombic
- Source of niobium, tantalum; metallurgic industry, high-technology apparatus
- Copper [Native copper]
- Copper-red
- # 2.5-3; Cubic
- Electronics industry, manufacture of alloys
- Covellite [Copper sulfide]
- Indigo blue
- # 1.5-2; Hexagonal
- Source of copper
- Enargite [Copper arsenic sulfide]
- Grey, iron-black
- # 3; Orthorhombic
- Source of copper and arsenic
- Galena [Lead sulfide]
- Lead-grey
- # 2.5; Cubic
- Source of lead, source of silver as by-product
- Geocronite [Lead antimony sulfide]
- Lead-grey to blue-grey
- # 2.5; Monoclinic
- Research, collections
- Goethite [Hydrous ferrous oxide]
- Grey-black, brown-red, bright yellow
- # 5-5.5; Orthorhombic
- Source of iron; yellow dyes
- Glaucodot [Iron cobalt arsenic sulfide]
- Tin-white, light grey
- # 5; Monoclinic
- Source of cobalt
- Gold [Native gold]
- Golden yellow
- # 2.5-3; Cubic
- Jewelry, coins, dental technology, electronic and scientifc equipment
- Name of Stone: Graphite [Native carbon]
- Dark grey, lead-grey
- # 1-2; Hexagonal
- Electronics, dyestuffs, refractories, industries; dry lubricant, lead for pencils
- Hauerite [Manganese sulfide]
- Chestnut-brown to blackish
- # 4; Cubic
- Research, collections
- Hematite [Iron oxide]
- Brown, red, iron-grey blue, green
- # 5-6; Trigonal
- Source of iron; pigment
- Ilmenite [Titanium iron oxide]
- Iron-black, black-red
- # 5-6; Trigonal
- Source of titanium
- Jamesonite [Lead iron antimony sulfide]
- Grey-black
- # 2.5; Monoclinic
- Minor source of lead
- Magnetite [Iron oxide]
- Black, iron-grey
- # 5.5-6.5; Cubic
- Source of iron
- Markasite [Iron sulfide]
- Golden yellow, brass-yellow
- # 6-6.5; Orthorhombic
- Production of sulfuric acid, costume jewelry in the past
- Mercury [Native mercury]
- Silver-white
- Liquid at normal temperatures; Trigonal when solidified
- Extraction of gold and silver formerly, electrotechnology, fungicides formerly
- Millerite [Nickel sulfide]
- Brassy-yellow to bronze
- # 3-3.5; Trigonal
- Minor source of nickel
- Molybdenite [Molybdenum sulfide]
- Lead-grey
- # 1-1.5; Hexagonal
- Source of molybdenum; special alloys, dry lubricant
- Niccolite [Nickel arsenide]
- Copper-red with light green
- # 5-5.5; Hexagonal
- Source of nickel
- Platinum [Native platinum]
- Silvery-grey
- # 4-4.5; Cubic
- Jewelry, catalyst, high-technology equipment
- Pyrite [Iron sulfide]
- Brass-yellow, golden yellow
- # 6-6.5; Cubic
- Production of sulfuric acid; source of gold, copper, nickel, iron as by products
- Pyrolusite [Manganese oxide]
- Iron-black, dark grey
- # 6-6.5; Tetragonal
- Source of manganese; iron industry, glassworks
- Pyrrhotite [Iron sulfide]
- Bronze to red
- # 3.5-4.5; Hexagonal
- Minor source of lead
- Silver [Native silver]
- Silvery white
- # 2.5-3; Cubic
- Chemical and electronics industries, jewelry, coins
- Skutterudite [Cobalt arsenide]
- Tin-white, steel grey
- # 5.5-6; Cubic
- Source of cobalt, arsenic, nickel
- Stilnite [Antimony sulfide]
- Lead-grey with red or yellow
- # 2; Orthorhombic
- Source of antimony; alloys, fireworks, electric batteries
- Sylvanite [Gold silver telluride]
- Light yellow
- # 1.5-2; Monoclinic
- Source of gold, silver, tellurium
- Tenorite [Copper oxide]
- Black, iron-grey, steel
- # 3.5; Monoclinic
- Minor source of copper
- Tetrahedrite [Copper sulfantimonide]
- Steel-black, iron-grey
- # 3-4.5; Cubic
- Source of copper, also of silver, mercury, and antimony
- Uraninite [Uranium oxide]
- Black, grey, green, chestnut-brown
- # 5-6; Cubic
- Source of uranium; in nuclear reactors; source of radium as a by-product
