Euxenite, or euxenite-(Y), is a brownish black mineral with a metallic luster.
Germanite is a rare copper iron germanium sulfide mineral, Cu26Fe4Ge4S32. It was first discovered in 1922, and named for its germanium content. It is only a minor source of this important semiconductor element, which is mainly derived from the processing of the zinc sulfide mineral sphalerite. Germanite contains gallium, zinc, molybdenum, arsenic, and vanadium as impurities.
Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms. The Mo-S bonds are strong, but the interaction between the sulfur atoms at the top and bottom of separate sandwich-like tri-layers is weak, resulting in easy slippage as well as cleavage planes. Molybdenite crystallizes in the hexagonal crystal system as the common polytype 2H and also in the trigonal system as the 3R polytype.
Fluororichterite is a rare amphibole with formula Na(NaCa)Mg5Si8O22F2.
Wulfenite is a lead molybdate mineral with the formula PbMoO4. It can be most often found as thin tabular crystals with a bright orange-red to yellow-orange color, sometimes brown, although the color can be highly variable. In its yellow form it is sometimes called "yellow lead ore".
Aurichalcite is a carbonate mineral, usually found as a secondary mineral in copper and zinc deposits. Its chemical formula is (Zn,Cu)5(CO3)2(OH)6. The zinc to copper ratio is about 5:4. Copper (Cu2+) gives aurichalcite its green-blue colors.
Natrolite is a tectosilicate mineral species belonging to the zeolite group. It is a hydrated sodium and aluminium silicate with the formula Na2Al2Si3O10·2H2O. The type locality is Hohentwiel, Hegau, Germany.
Arfvedsonite is a sodium amphibole mineral with composition: [Na][Na2][(Fe2+)4Fe3+][(OH)2|Si8O22]. It crystallizes in the monoclinic prismatic crystal system and typically occurs as greenish black to bluish grey fibrous to radiating or stellate prisms.
Vauquelinite is a complex mineral with the formula CuPb2(CrO4)(PO4)(OH) making it a combined chromate and phosphate of copper and lead. It forms a series with the arsenate mineral fornacite.
Chloritoid is a silicate mineral of metamorphic origin. It is an iron magnesium manganese alumino-silicate hydroxide with formula (Fe, Mg, Mn)
2Al
4Si
2O
10(OH)
4. It occurs as greenish grey to black platy micaceous crystals and foliated masses. Its Mohs hardness is 6.5, unusually high for a platy mineral, and it has a specific gravity of 3.52 to 3.57. It typically occurs in phyllites, schists and marbles.
Agrellite (NaCa2Si4O10F) is a rare triclinic inosilicate mineral with four-periodic single chains of silica tetrahedra.
Aliettite is a complex phyllosilicate mineral of the smectite group with a formula of (Ca0.2Mg6(Si,Al)8O20(OH)4·4H2O) or [Mg3Si4O10(OH)2](Ca0.5,Na)0.33(Al,Mg,Fe2+)2−3(Si,Al)4O10(OH)2·n(H2O).
Portlandite is a hydroxide-bearing mineral typically included in the oxide mineral class. It is the naturally occurring form of calcium hydroxide (Ca(OH)2) and the calcium analogue of brucite (Mg(OH)2).
Ekanite is an uncommon silicate mineral with chemical formula Ca
2ThSi
8O
20 or (Ca,Fe,Pb)
2(Th,U)Si
8O
20. It is a member of the steacyite group. It is among the few gemstones that are naturally radioactive. Most ekanite is mined in Sri Lanka, although deposits also occur in Russia and North America. Clear and well-colored stones are rare as the radioactivity tends to degrade the crystal matrix over time in a process known as metamictization.
Patrónite is the vanadium sulfide mineral with formula VS4. The material is usually described as V4+(S22−)2. Structurally, it is a "linear-chain" compound with alternating bonding and nonbonding contacts between the vanadium centers. The vanadium is octa-coordinated, which is an uncommon geometry for this metal.
Anapaite is a calcium–iron phosphate mineral with formula: Ca2Fe2+(PO4)2·4H2O. It is a mineral that typically occurs in cavities in fossil bearing sedimentary rocks. It is also found in phosphate bearing iron ores and rarely in pegmatites. It is commonly found with goethite, siderite and vivianite.
Hsianghualite is a tectosilicate of lithium, calcium and beryllium, with fluorine, a member of the zeolite group. It was discovered in 1958 and named for the type locality, Hsiang Hua, 香花, meaning fragrant flower.
Hemusite is a very rare isometric gray mineral containing copper, molybdenum, sulfur, and tin with chemical formula Cu6SnMoS8. It was discovered by Bulgarian mineralogist Georgi Ivanov Terziev in 1963. He also described it and named it after Haemus, the ancient name of Stara planina (Balkan) mountains in Europe. The type locality is Chelopech copper ore deposit, Bulgaria. Later tiny deposits of hemusite were found in Ozernovskoe deposit, Kamchatka, Russia; Kawazu mine, Rendaiji, Shimoda city, Chūbu region, Honshu Island, Japan; Iriki mine, Iriki, Satsuma-gun, Kagoshima Prefecture, Kyushu Region, Japan; Kochbulak deposit, Tashkent, Uzbekistan. Hemusite occurs as rounded isometric grains and aggregates usually about 0.05 mm in diameter and in association with enargite, luzonite, colusite, stannoidite, renierite, tennantite, chalcopyrite, pyrite, and other minerals.
Ferrimolybdite is a hydrous iron molybdate mineral with formula: Fe3+2(MoO4)3·8(H2O) or Fe3+2(MoO4)3·n(H2O). It forms coatings and radial aggregates of soft yellow needles which crystallize in the orthorhombic system.
Piypite is a rare potassium, copper sulfate mineral with formula: K2Cu2O(SO4)2. It crystallizes in the tetragonal system and occurs as needlelike crystals and masses. Individual crystals are square in cross-section and often hollow. It is emerald green to black in color with a vitreous to greasy luster.
