Sodalite is a tectosilicate mineral with the formula Na
8(Al
6Si
6O
24)Cl
2, with royal blue varieties widely used as an ornamental gemstone. Although massive sodalite samples are opaque, crystals are usually transparent to translucent. Sodalite is a member of the sodalite group with hauyne, nosean, lazurite and tugtupite.
Stilbite is the name of a series of tectosilicate minerals of the zeolite group. Prior to 1997, stilbite was recognized as a mineral species, but a reclassification in 1997 by the International Mineralogical Association changed it to a series name, with the mineral species being named:
Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with the orthorhombic barium (baryte) and strontium (celestine) sulfates, as might be expected from the chemical formulas. Distinctly developed crystals are somewhat rare, the mineral usually presenting the form of cleavage masses. The Mohs hardness is 3.5, and the specific gravity is 2.9. The color is white, sometimes greyish, bluish, or purple. On the best developed of the three cleavages, the lustre is pearly; on other surfaces it is glassy. When exposed to water, anhydrite readily transforms to the more commonly occurring gypsum, (CaSO4·2H2O) by the absorption of water. This transformation is reversible, with gypsum or calcium sulfate hemihydrate forming anhydrite by heating to around 200 °C (400 °F) under normal atmospheric conditions. Anhydrite is commonly associated with calcite, halite, and sulfides such as galena, chalcopyrite, molybdenite, and pyrite in vein deposits.
Alunite is a hydroxylated aluminium potassium sulfate mineral, formula KAl3(SO4)2(OH)6. It was first observed in the 15th century at Tolfa, near Rome, where it was mined for the manufacture of alum. First called aluminilite by J.C. Delamétherie in 1797, this name was contracted by François Beudant three decades later to alunite.
Austinite is a member of the adelite-descloizite group, adelite subgroup, the zinc (Zn) end member of the copper-Zn series with conichalcite. It is the zinc analogue of cobaltaustinite and nickelaustinite. At one time “brickerite” was thought to be a different species, but it is now considered to be identical to austinite. Austinite is named in honour of Austin Flint Rogers (1877–1957), American mineralogist from Stanford University, California, US.
Lorándite is a thallium arsenic sulfosalt with the chemical formula: TlAsS2. Though rare, it is the most common thallium-bearing mineral. Lorandite occurs in low-temperature hydrothermal associations and in gold and mercury ore deposits. Associated minerals include stibnite, realgar, orpiment, cinnabar, vrbaite, greigite, marcasite, pyrite, tetrahedrite, antimonian sphalerite, arsenic and barite.
Ajoite is a hydrated sodium potassium copper aluminium silicate hydroxide mineral. Ajoite has the chemical formula (Na,K)Cu7AlSi9O24(OH)6·3H2O, and minor Mn, Fe and Ca are usually also present in the structure. Ajoite is used as a minor ore of copper.
Aguilarite is an uncommon sulfosalt mineral with formula Ag4SeS. It was described in 1891 and named for discoverer Ponciano Aguilar.
Getchellite is a rare sulfide of arsenic and antimony, AsSbS3, that was discovered by B. G. Weissberg of the New Zealand Department of Scientific and Industrial Research in 1963, and approved as a new species by the International Mineralogical Association in 1965. Many metal sulfides are grey to black, but a few are brightly colored. Orpiment is yellow to brownish gold, cinnabar is deep red and getchellite is a bright orange red.
Frankdicksonite is a halide mineral with the chemical formula BaF2 which corresponds to the chemical compound barium fluoride. It occurs in the Carlin gold deposit of Eureka County, Nevada as cubic crystals sized between 0.1 and 4 mm, and is of hydrothermal origin. Its only associated mineral is quartz and the frankdicksonite crystals are always completely encapsulated in it. Frankdicksonite has fluorite crystal structure with a cubic symmetry and the lattice constant a = 619.64 pm. Its Vickers hardness on the {111} cleavage crystal faces varies between 88 and 94 kg/mm2 and is close to that of the synthetic barium fluoride (95 kg/mm2). Its refractive index (1.475) is almost identical to that of BaF2 (1.474). Under electron irradiation, it emits strong blue cathodoluminescence. The major impurity in frankdicksonite is strontium with concentrations up to 0.5% by weight. Also present are silicon (0.02%) and magnesium (0.0015%); other impurities have concentrations below 0.0015%.
Tsumebite is a rare phosphate mineral named in 1912 after the locality where it was first found, the Tsumeb mine in Namibia, well known to mineral collectors for the wide range of minerals found there. Tsumebite is a compound phosphate and sulfate of lead and copper, with hydroxyl, formula Pb2Cu(PO4)(SO4)(OH). There is a similar mineral called arsentsumebite, where the phosphate group PO4 is replaced by the arsenate group AsO4, giving the formula Pb2Cu(AsO4)(SO4)(OH). Both minerals are members of the brackebuschite group.
Mendipite is a rare mineral that was named in 1939 for the locality where it is found, the Mendip Hills in Somerset, England. It is an oxyhalide of lead with formula Pb3Cl2O2.
Hagendorfite is an iron phosphate mineral with the chemical formula of (Na,Ca)MnFe2(PO4)3 and is named after where the mineral was discovered, Hagendorf-Süd, Bavaria, Germany.
Babefphite is a rare phosphate mineral with the general formula BaBe(PO4)(F,OH). The name is given for its composition (Ba meaning barium, Be meaning beryllium, F meaning fluorine, and P for phosphorus).
Malayaite is a calcium tin silicate mineral with formula CaSnOSiO4. It is a member of the titanite group.
The silver antimonide mineral dyscrasite has the chemical formula Ag3Sb. It is an opaque, silver white, metallic mineral which crystallizes in the orthorhombic crystal system. It forms pyramidal crystals up to 5 cm (2.0 in) and can also form cylindrical and prismatic crystals.
Fluoborite has a chemical formula of Mg3(BO3)(F,OH)3. Its name comes from its main chemical components, FLUOrine and BORon. It was first described in 1926.
Tsumcorite is a rare hydrated lead arsenate mineral that was discovered in 1971, and reported by Geier, Kautz and Muller. It was named after the TSUMeb CORporation mine at Tsumeb, in Namibia, in recognition of the Corporation's support for mineralogical investigations of the orebody at its Mineral Research Laboratory.
Nevadaite is a rare phosphate mineral with a chemical formula of
Waterhouseite, Mn7(PO4)2(OH)8, is a hydroxy manganese phosphate mineral. It is a medium-soft, brittle mineral occurring in pseudo-orthorhombic monoclinic bladed crystals and orange-brown to dark brown in color. Waterhouseite is on the softer side with a Mohs hardness of 4, has a specific gravity of 3.5 and a yellowish-brown streak. It is named after Frederick George Waterhouse, first director of the South Australian Museum, as well as recognizes the work Waterhouse Club has done in support of the South Australian Museum.
