Category
page 2Oxide minerals

cervantite
Cervantite, also formerly known as antimony ochre — is an antimony oxide mineral with formula Sb3+Sb5+O4 (antimony tetroxide).
fergusonite-(REE) series
Fergusonite is a mineral comprising a complex oxide of various rare-earth elements. The general chemical formula of fergusonite is (Y,REE)NbO4, where REE = rare-earth elements in solid solution with Y. Yttrium is usually dominant (the mineral in this case being referred to as fergusonite-(Y)), but sometimes Ce or Nd may be the major rare-earth component (in fergusonite-(Ce) and fergusonite-(Nd), respectively). The other rare-earth elements are present in smaller amounts, and tantalum sometimes substitutes for some of the niobium. There are fergusonite-beta-(Nd), fergusonite-beta-(Y), fergusoni

carmeltazite
thumb|Crystal structure of carmeltazite
thumb|Mount Carmel|Carmel Sapphire
Carmeltazite is a rare oxide mineral. Its first discovery on Earth was announced in 2019, after it was found in Zebulun Valley in Israel. The chemical formula for carmeltazite is ZrAl2Ti4O11.
hercynite
Hercynite is a spinel mineral with the formula FeAl2O4.
stibiconite
Stibiconite, also formerly known as stiblite or antimony ochre is an antimony oxide mineral with formula: Sb3O6(OH). Its name originates from Greek (), 'antimony' and (), 'powder', alluding to its composition and habit. It is a member of the pyrochlore super group.
manganosite
Manganosite is a rare mineral composed of manganese(II) oxide MnO. It was first described in 1817 for an occurrence in the Harz Mountains, Saxony-Anhalt, Germany. It has also been reported from Langban and Nordmark, Sweden and at Franklin Furnace, New Jersey. It also occurs in Japan, Kyrgyzstan and Burkina Faso.
allactite
Allactite is a rare arsenate mineral of metamorphosed manganese zinc ore deposits. It is found in Sweden and New Jersey, US. Its name originated from the Greek αλλάκτειν (allaktein) meaning "to change", referring to the strong pleochroism of the mineral.
molybdite
Molybdite is the naturally occurring mineral form of molybdenum trioxide MoO3. It occurs as yellow to greenish needles and crystallizes in the orthorhombic crystal system.
mogánite
Moganite is a tectosilicate mineral with the chemical formula SiO2 (silicon dioxide) that was discovered in 1976. The mineral was initially described as a new form of silica, on the basis of specimens found in the Barranco de Medio Almud ravine. This ravine is in the municipality of Mogán, on the island of Gran Canaria, in the Canary Islands region of Spain. In later work, the mineral derived its name from this locality. In 1994, the International Mineralogical Association (IMA) disapproved moganite as a valid mineral, since it was considered to be indistinguishable from quartz. Subsequent stu
ulvöspinel
Ulvöspinel or ulvite is an iron titanium oxide mineral with formula: Fe2TiO4 or TiFe2+2O4. It forms brown to black metallic isometric crystals with a Mohs hardness of 5.5 to 6. It belongs to the spinel group of minerals, as does magnetite, Fe3O4.
galaxite
Galaxite, also known as 'mangan-spinel' is an isometric mineral belonging to the spinel group of oxides with the ideal chemical formula .
It is sometimes used as a gemstone.
studtite
Studtite, chemical formula [(UO2)O2(H2O)2]·2(H2O) or UO4·4(H2O), is a secondary uranium mineral containing peroxide produced by the alpha-radiolysis of water during its formation. It occurs as pale yellow to white needle-like crystals often in acicular, white sprays.

plattnerite
Plattnerite is an oxide mineral and is the beta crystalline form of lead dioxide (β-PbO2), scrutinyite being the other, alpha form. It was first reported in 1845 and named after German mineralogist Karl Friedrich Plattner. Plattnerite forms bundles of dark needle-like crystals on various minerals; the crystals are hard and brittle and have tetragonal symmetry.
aeschynite-(Y)
Aeschynite-(Y) (or Aeschinite-(Y), Aeschynite-(Yt), Blomstrandine, Priorite) is a rare earth mineral of yttrium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with the chemical formula . Its name comes from the Greek word for "shame". Its Mohs scale rating is 5 to 6.
bromellite
Bromellite, whose name derives from the Swedish chemist Magnus von Bromell (1670–1731), is a white oxide mineral. The mineral form of beryllium oxide, it is found in complex pegmatitic manganese-iron deposits, but is more frequently made synthetically. This is a rare mineral to encounter in its natural state, but it has been made synthetically for over 40 years.
clarkeite
Clarkeite is a uranium oxide mineral with the chemical formula or .
agrinierite
Agrinierite is a mineral often found in the oxidation zone of uranium deposits. It is named after Henry Agrinier (1928–1971), a French engineer for the Commissariat à l'Énergie Atomique
(Mineralogy Laboratory of the French Atomic Energy Commission, Paris, France). Agrinierite is a hydrated oxide of uranium discovered during the exploitation of the uranium deposit of Margnac (Haute-Vienne, France), the only site in the world where it is known today.
It appears at the periphery of uraninite nodules accompanied by other uranium oxides which result like it from the transformation of uraninite (bec
magnesioferrite
Magnesioferrite is a magnesium iron oxide mineral, a member of the magnetite series of spinels.
Magnesioferrite crystallizes as black metallic octahedral crystals. It is named after its chemical composition of magnesium and ferric iron.
The density is 4.6 - 4.7 (average = 4.65), and the diaphaniety is opaque. Occurs as well-formed fine sized crystals or massive and granular.
Its hardness is 6-6.5. It has a metallic luster and a dark red streak.
argutite
Argutite (GeO2) is a rare germanium oxide mineral. It is a member of the rutile group.
hibonite
Hibonite is a mineral with the chemical formula , occurring in various colours, with a hardness of 7.5–8.0 and a hexagonal crystal structure. It is rare, but is found in high-grade metamorphic rocks on Madagascar. Some presolar grains in primitive meteorites consist of hibonite. Hibonite also is a common mineral in the Ca-Al-rich inclusions found in some chondritic meteorites. Hibonite is closely related to hibonite-Fe (IMA 2009-027, ) an alteration mineral from the Allende meteorite. Hibonites were among the first minerals to form as the disk of gas and dust swirling around the young sun cool
margaritasite
Margaritasite is a yellow, caesium-bearing mineral in the carnotite group. Its chemical formula is (Cs, K, H3O)2(UO2)2V2O8·H2O and its crystal system is monoclinic (space group P21/a).
lópezite
Lópezite is a rare red chromate mineral with chemical formula: K2Cr2O7. It crystallizes in the triclinic crystal system.

todorokite
thumb|Polyhedral representation of the todorokite structure.
leucoxene
Leucoxene is a fine granular alteration product of titanium minerals. It varies in color from yellow to brown.
eskolaite
Eskolaite is a rare chromium oxide mineral (chromium(III) oxide Cr2O3).
pseudobrookite
Pseudobrookite is an iron titanium oxide mineral with formula: Fe2TiO5 or (Fe3+,Fe2+)2(2+)O5.
bismoclite
Bismoclite is a bismuth oxohalide mineral with formula BiOCl. It is the naturally occurring form of bismuth oxychloride. The name was derived from its chemical constituents. It is a secondary bismuth mineral first thought to be composed of bismuthyl ions (BiO+) and chloride anions, however, the existence of the diatomic bismuthyl ion is doubtful.
asbolane
Asbolane, previously cobalt ochre is a manganese (IV) oxy-hydroxide mineral containing also cobalt, nickel, magnesium, and calcium ions. It crystallizes in the hexagonal crystal system. Its chemical formula is .

paramelaconite
Paramelaconite is a rare, black-colored copper(I,II) oxide mineral with formula CuCuO3 (or Cu4O3). It was discovered in the Copper Queen Mine in Bisbee, Arizona, about 1890. It was described in 1892 and more fully in 1941. Its name is derived from the Greek word for "near" and the similar mineral melaconite, now known as tenorite.
groutite
Groutite is a manganese oxide mineral with formula Mn3+O(OH). It is a member of the diaspore group and is trimorphous with manganite and feitknechtite. It forms lustrous black crystals in the orthorhombic system.
pyrophanite
Pyrophanite is a manganese titanium oxide mineral with formula: MnTiO3. It is a member of the ilmenite group. It is a deep red to greenish black mineral which crystallizes in the trigonal system.
brownmillerite
Brownmillerite is a rare oxide mineral with chemical formula . It is named for Lorrin Thomas Brownmiller (1902–1990), chief chemist of the Alpha Portland Cement Company, Easton, Pennsylvania.
zirconolite
Zirconolite is a mineral, calcium zirconium titanate; formula CaZrTi2O7. Some examples of the mineral may also contain thorium, uranium, cerium, niobium and iron; the presence of thorium or uranium would make the mineral radioactive. It is black or brown in color.
tausonite
Tausonite is the rare naturally occurring mineral form of strontium titanate: chemical formula: SrTiO3. It occurs as red to orange brown cubic crystals and crystal masses.
strunzite
Strunzite (Mn2+Fe3+2(PO4)2(OH)26H2O) is a light yellow mineral of the strunzite group, first discovered in 1957.

claudetite
thumb
Claudetite is an arsenic oxide mineral with chemical formula As2O3. Claudetite is formed as an oxidation product of arsenic sulfides and is colorless or white. It can be associated with arsenolite (the cubic form of As2O3) as well as realgar (As4S4), orpiment (As2S3) and native sulfur.
montroydite
Montroydite is the mineral form of mercury(II) oxide with formula HgO. It is a rare mercury mineral. It was first described for an occurrence in the mercury deposit at Terlingua, Texas and named for Montroyd Sharp who was an owner of the deposit.

romanèchite
thumb|Polyhedral representation of the 2 x 3 tunnel structure of romanèchite. The red atoms represent Ba and H2O.
polycrase-(Y)
Polycrase or polycrase-(Y) is a black or brown metallic complex uranium yttrium oxide mineral with the chemical formula . It is amorphous. It has a Mohs hardness of 5 to 6 and a specific gravity of 5. It is radioactive due to its uranium content (around 6%). It occurs in granitic pegmatites.
cryptomelane
Cryptomelane (K(Mn4+,Mn2+)8O16) is the potassium endmember of the hollandite group, a family of tectomanganates with a 2 × 2 tunnel structure.
aeschynite-(Ce)
Aeschynite-(Ce) (or Aschynite, Eschinite, Eschynite) is a rare earth mineral of cerium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with chemical formula . Its name comes from the Greek word αισχύνη ("aeschyne") for "shame" because early chemists had difficulty with separations of titanium from zirconium.
wad
porous secondary manganese oxides, mainly
sabinaite
Sabinaite (Na4Zr2TiO4(CO3)4) is a rare carbonate mineral. It crystallizes in the monoclinic crystal system as colorless to white prisms within cavities. It is more typically found as powdery coatings and masses. It has a specific gravity of 3.36.
karelianite
Karelianite is an rare mineral, a natural form of vanadium(III) oxide, V2O3. In terms of chemistry it is vanadium-analogue of hematite, corundum, eskolaite, tistarite, bixbyite, avicennite, and yttriaite-(Y). The name comes from Karelia, a region on the Finnish-Russian border. It may be associated with magnesium-rich rocks.
akaganeite
Akaganeite, also written as the deprecated Akaganéite, is a chloride-containing iron(III) oxide-hydroxide mineral, formed by the weathering of pyrrhotite (Fe1−xS), an iron-deficient sulfide.
roméite
Roméite is a calcium antimonate mineral with the chemical formula . It is a honey-yellow mineral crystallizing in the hexoctahedral crystal system. It has a Mohs hardness of 5.5-6.0. It occurs in Algeria, Australia, Brazil, China, Europe, Japan, New Zealand, and the United States in metamorphic iron-manganese deposits and in hydrothermal antimony-bearing veins.
chlormayenite
Chlormayenite (after Mayen, Germany), Ca12Al14O32[☐4Cl2], is a rare calcium aluminium oxide mineral of cubic symmetry.
feroxyhyte
Feroxyhyte is an oxide/hydroxide of iron, δ-Fe3+O(OH). Feroxyhyte crystallizes in the hexagonal system. Feroxyhyte forms as brown, rounded to concretionary masses. Feroxyhyte is an opaque, magnetic mineral with a yellow streak and a relative density of 4.2.
quetzalcoatlite
Quetzalcoatlite is a rare tellurium oxysalt mineral with the formula Zn6Cu3(TeO6)2(OH)6 · AgxPbyClx+2y. It also contains large amounts of silver- and lead(II)chloride with the formula AgxPbyClx+2y (x+y≤2). It has a Mohs hardness of 3 and it crystallizes in the trigonal system. It has a deep blue color. It was named after Quetzalcoatl, the Aztec and Toltec god of the sea, alluding to its color. It is not to be confused with tlalocite, which has a similar color and habit.
magnesiotaaffeite-6N'3S
Musgravite or magnesiotaaffeite-6N’3S is a rare oxide mineral used as a gemstone. Its type locality is the Ernabella Mission, Musgrave Ranges, South Australia, for which it was named following its discovery in 1967. It is a member of the taaffeite family of minerals, and its chemical formula is Be(Mg, Fe, Zn)2Al6O12. Its hardness is 8 to 8.5 on the Mohs scale. Due to its rarity, the mineral can sell for roughly USD$35,000 per carat.
zirkelite
Zirkelite is an oxide mineral with the chemical formula . It occurs as well-formed fine sized isometric crystals. It is a black, brown or yellow mineral with a hardness of 5.5 and a specific gravity of 4.7.
masuyite
Masuyite is a uranium/lead oxide mineral with formula Pb[(UO2)3O3(OH)2]·3H2O.
simpsonite
Simpsonite has a general formula of . It occurs as euhedral to subhedral tabular to short and prismatic crystals, commonly in subparallel groups. Under the petrographic microscope it has a very high relief.
delafossite
Delafossite is a copper iron oxide mineral with formula CuFeO2 or Cu1+Fe3+O2. It is a member of the delafossite mineral group, which has the general formula ABO2, a group characterized by sheets of linearly coordinated A cations stacked between edge-shared octahedral layers (BO6). Delafossite, along with other minerals of the ABO2 group, is known for its wide range of electrical properties, its conductivity varying from insulating to metallic. Delafossite is usually a secondary mineral that crystallizes in association with oxidized copper and rarely occurs as a primary mineral.
panguite
Panguite is a type of titanium oxide mineral first discovered as an inclusion within the Allende meteorite, and first described in 2012.
cafarsite
Cafarsite (·)
is a rare calcium iron arsenite mineral. Manganese and titanium occur with iron in the formula.
tungstite
Tungstite is a hydrous tungsten oxide mineral with formula: WO3·H2O. It is a secondary mineral formed by the weathering of other tungsten containing minerals. It crystallizes in the orthorhombic system in translucent yellow to yellow green masses. It is clay-like with Mohs hardness of 2.5 and a specific gravity of 5.5.
cafetite
Cafetite is a rare titanium oxide mineral with formula ·. It is named for its composition, Ca-Fe-Ti.
ferropericlase
Ferropericlase or magnesiowüstite is a magnesium/iron oxide with the chemical formula that is interpreted to be one of the main constituents of the Earth's lower mantle together with the silicate perovskite (), a magnesium/iron silicate with a perovskite structure. Ferropericlase has been found as inclusions in a few natural diamonds. An unusually high iron content in one suite of diamonds has been associated with an origin from the lowermost mantle. Discrete ultralow-velocity zones in the deepest parts of the mantle, near the Earth's core, are thought to be blobs of ferropericlase, as seismic
fingerite
Fingerite is a copper vanadate mineral with formula: β-Cu2V2O5. It was discovered as triclinic crystals occurring as volcanic sublimates around fumaroles in the crater of the Izalco Volcano, El Salvador.