Rutile is an oxide mineral composed of titanium dioxide (TiO2), the most common natural form of TiO2. Rarer polymorphs of TiO2 are known, including anatase, akaogiite, and brookite.
Proustite is a sulfosalt mineral consisting of silver sulfarsenide, Ag3AsS3, known also as ruby blende, light red silver, arsenic-silver blende or ruby silver ore, and an important source of the metal. It is closely allied to the corresponding sulfantimonide, pyrargyrite, from which it was distinguished by the chemical analyses of Joseph L. Proust (1754–1826) in 1804, after whom the mineral received its name.
Dickite is a phyllosilicate clay mineral named after the metallurgical chemist Allan Brugh Dick, who first described it. It is chemically composed of 20.90% aluminium, 21.76% silicon, 1.56% hydrogen and 55.78% oxygen. It has the same composition as kaolinite, nacrite, and halloysite, but with a different crystal structure (polymorph). Dickite sometimes contains impurities such as titanium, iron, magnesium, calcium, sodium and potassium.
Pyrargyrite is a sulfosalt mineral consisting of silver sulfantimonite, Ag3SbS3. Known also as dark red silver ore, ruby blende, garnete blende or ruby silver, it is an important source of the metal.
Leadhillite is a lead sulfate carbonate hydroxide mineral, often associated with anglesite. It has the formula Pb4SO4(CO3)2(OH)2. Leadhillite crystallises in the monoclinic system, but develops pseudo-hexagonal forms due to crystal twinning. It forms transparent to translucent variably coloured crystals with an adamantine lustre. It is quite soft with a Mohs hardness of 2.5 and a relatively high specific gravity of 6.26 to 6.55.
Sulfosalt minerals are sulfide minerals with the general formula AmBnXp, where
Afwillite is a calcium hydroxide nesosilicate mineral with formula Ca3(SiO3OH)2·2H2O. It occurs as glassy, colorless to white prismatic monoclinic crystals. Its Mohs scale hardness is between 3 and 4. It occurs as an alteration mineral in contact metamorphism of limestone. It occurs in association with apophyllite, natrolite, thaumasite, merwinite, spurrite, gehlenite, ettringite, portlandite, hillebrandite, foshagite, brucite and calcite.
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.
Bararite is a natural form of ammonium fluorosilicate (also known as hexafluorosilicate or fluosilicate). It has chemical formula (NH4)2SiF6 and trigonal crystal structure. This mineral was once classified as part of cryptohalite. Bararite is named after the place where it was first described, Barari in Jharia Coal Field, Dhanbad, India. It is found at the fumaroles of volcanoes (Vesuvius, Italy), over burning coal seams (Barari, India), and in burning piles of anthracite (Pennsylvania, U.S.). It is a sublimation product that forms with cryptohalite, sal ammoniac, and native sulfur.
Cesanite is the end member of the apatite-wilkeite-ellestadite series that substitutes all of apatite's phosphate ions with sulfate ions and balances the difference in charge by replacing several calcium ions with sodium ions. Currently very few sites bearing cesanite have been found and are limited to a geothermal field in Cesano, Italy from which its name is derived, Măgurici Cave in Romania, and in the San Salvador Island caves in the Bahamas.
Magnesiohastingsite is a calcium-containing amphibole and a member of the hornblende group. It is an inosilicate (chain silicate) with the formula NaCa2(Mg4Fe3+)(Si6Al2)O22(OH)2 and molar mass 864.69 g. In synthetic magnesiohastingsite it appears that iron occurs both as ferrous iron Fe2+ and as ferric iron Fe3+, but the ideal formula features only ferric iron. It was named in 1928 by Marland P. Billings. The name is for its relationship to hastingsite and its magnesium content. Hastingsite was named for the locality in Dungannon Township, Hastings County, Ontario, Canada.
Bursaite is a sulfosalt of the lillianite family. It has the formula Pb5Bi4S11 and orthorhombic structure. Bursaite is named after Bursa Province, Turkey, where it was discovered. It is generally located in regions rich in sulfur and commonly occurs alongside other sulfosalts. Its areas of formation are usually those that were once volcanogenic because it is generally aggregated with other minerals under intense heating. It was officially delisted as a mineral in 2006, being cited as an intergrowth of two other sulfosalts.
Hidalgoite, PbAl3(AsO4)(SO4)(OH)4, is a rare member of the beudantite group and is usually classified as part of the alunite family. It was named after the place where it was first discovered, the Zimapán mining district, Hidalgo, Mexico. At Hidalgo where it was initially discovered, it was found as dense white masses in alternating dikes of quartz latite and quartz monzonite alongside other secondary minerals such as sphalerite, arsenopyrite, cerussite and trace amounts of angelsite and alamosite, it was then rediscovered at other locations such as Australia where it occurs on oxidized shear zones above greywacke shales especially on the anticline prospects of the area, and on fine grained quartz-spessartine rocks in Broken Hill, Australia. Hidalgoite specimens are usually associated with copper minerals, clay minerals, iron oxides and polymetallic sulfides in occurrence.
The mineral hubeite, Ca
2Mn2+
Fe3+
[Si
4O
12(OH)]·(H
2O)
2, is a sorosilicate of the Si
4O
13 group. Structurally it also belongs to the Akatoreite group. It was found and named after the province of Hubei, China. It is common to iron ores in a mine of that region. It occurs mainly as aggregates of fan like crystals. It is dark to pale brown, has orange-brown streak and is vitreous. Hubeite has a hardness of 5.5 in the Mohs scale, one good cleavage and conchoidal fracture. It is triclinic with a space group of P1*. The structure of hubeite is very uncommon, and in fact there is only one other mineral that fits the Si
4O
13 group, which is ruizite.
Leifite is a rare tectosilicate. Tectosilicates are built on a framework of tetrahedra with silicon or aluminium at the centre and oxygen at the vertices; they include feldspars and zeolites, but leifite does not belong in either of these categories. It is a member of the leifite group, which includes telyushenkoite (Cs,Na,K)Na6(Be2Al3Si15O39) and eirikite KNa6Be2(Si15Al3)O39F2). Leifite was discovered in 1915, and named after Leif Ericson who was a Norse explorer who lived around 1000 AD, and was probably the first European to land in North America, nearly 500 years before Christopher Columbus. Eirikite was named in 2007 after Eirik Raude, or Erik the Red, (950–1003), who discovered Greenland and who was the father of Leif Ericson. The third mineral in the group, telyushenkoite, was discovered in 2001. It was not named after any of Leif Ericson's family members, but after a professor of geology in Turkmenistan.
Sheldrickite is a sodium calcium carbonate fluoride mineral, named in honor of George M. Sheldrick, former Professor of Crystallography at the University of Göttingen in Germany. Sheldrick is the creator of SHELLX computer program widely used for the analysis of crystal structures. Determination of the structure of this mineral required the software's capability of handling twinned crystals.
Rockbridgeite is an anhydrous phosphate mineral in the "Rockbridgeite" supergroup with the chemical formula Fe2+Fe3+4(PO4)3(OH)5. It was discovered at the since-shut-down Midvale Mine in Rockbridge County, Virginia, United States. The researcher who first identified it, Clifford Frondel, named it in 1949 for its region of discovery, Rockbridge County.
Raygrantite is a mineral first discovered in Big Horn Mountains, Maricopa County, Arizona, US. More specifically, it is located in the evening star mine, which is a Cu, V, Pb, Ag, Au, and W mine. Raygrantite is a member of the iranite mineral group, which consists of hemihedrite, iranite, and raygrantite. This mineral received its name in honor of Raymond W. Grant, a retired professor who primarily focused on the minerals of Arizona. The typical crystal structure of raygrantite is bladed with parallel striations to the C axis. Its ideal chemical formula is Pb10Zn(SO4)6(SiO4)2(OH)2. The IMA (International Mineralogical Association) approved raygrantite in 2013, and the first publication regarding this mineral was put forth in 2017.
Rayite, a monoclinic mineral containing Lead-Silver-Thallium-Antimony, was found during microscopic and electron microprobe study of specimens from the complex, polymetallic sulphide-native metal sulpho-salt paragenesis of Rajpura-Dariba, Rajasthan, India. It is named after Dr. Santosh K. Ray of President College, Calcutta, India. It bears a striking resemblance to owyheeite in terms of its Lead/(Silver,Thallium)/Antimony ratio, yet its structural affinity lies with Semseyite. The average composition is Lead-47.06, Copper-0.03, Silver-4.54, Thallium-2.04, Antimony-27.42, Sulphur-19.59 by wt.% (total 100.68) suggesting an ideal formula of Pb8(Ag,Tl)2Sb8S21, where Ag > Tl. Meneghinite, Owyheeite, and Galena are related minerals.
Chvilevaite (Russian: чвилеваи́т, чвилёваи́т, in its own name) is a rare hydrothermal polymetallic mineral from the class of complex sulfides, forming microscopic grains in related minerals, its composition is a rare combination of alkali (combining lithophile) and chalcophile metals — sodium ferro-sulfide, zinc and copper with the calculation formula Na(Cu,Fe,Zn)2S4, originally published and confirmed as Na(Cu,Fe,Zn)2S2.
