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Tokyoite displayed at Mining Museum of Akita University.jpg
Tokyoite ore displayed at the Mining Museum of Akita University, Japan
CategoryVanadate mineral
(repeating unit)
IMA symbol Tky [1]
Strunz classification 8.BG.05
Crystal system Monoclinic
Crystal class Prismatic (2/m)
(same H-M symbol)
Unit cell a = 9.104  Å, b = 6.132 Å
c = 7.895 Å; β = 112.2°; Z = 2
ColorReddish black
Crystal habit Occurs as splotchy, anhedral crystals forming inclusions
Cleavage None observed
Mohs scale hardness4.5 - 5
Luster Vitreous
Streak Deep brownish red
Diaphaneity Translucent
Specific gravity 4.62 calculated
Optical propertiesBiaxial (?)
Refractive index a=1.99, g=2.03
Birefringence 0.0400
Pleochroism Distinct, reddish orange to dark brownish red
References [2] [3] [4]

Tokyoite is a rare barium manganese vanadate mineral with the chemical formula: Ba2(Mn3+,Fe3+)OH(VO4)2. It is the manganese analogue of the iron rich gamagarite [3] and the barium analogue of the lead vanadate, brackebuschite. [4]

It occurs in low-grade metamorphosed sedimentary manganese ore deposits [2] associated with hyalophane, braunite and tamaite. [4]

It was first reported for an occurrence in the Shiromaru Mine, Okutama, Tama district, Tokyo Prefecture, Kantō region, Honshu Island, Japan and approved by the IMA in 2003. [3] It has been found in two mines in Italy and one in Japan, for which it was named. [2]

Related Research Articles

<span class="mw-page-title-main">Axinite</span>

Axinite is a brown to violet-brown, or reddish-brown bladed group of minerals composed of calcium aluminium boro-silicate, (Ca,Fe,Mn)3Al2BO3Si4O12OH. Axinite is pyroelectric and piezoelectric.

<span class="mw-page-title-main">Carnotite</span> Radioactive mineral

Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula K2(UO2)2(VO4)2·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.

<span class="mw-page-title-main">Todorokite</span> Hydrous manganese oxide mineral

Todorokite is a rare complex hydrous manganese oxide mineral with the chemical formula (Na,Ca,K,Ba,Sr)
. It was named in 1934 for the type locality, the Todoroki mine, Hokkaido, Japan. It belongs to the prismatic class 2/m of the monoclinic crystal system, but the angle β between the a and c axes is close to 90°, making it seem orthorhombic. It is a brown to black mineral which occurs in massive or tuberose forms. It is quite soft with a Mohs hardness of 1.5, and a specific gravity of 3.49 - 3.82. It is a component of deep ocean basin manganese nodules.

Geigerite is a mineral, a complex hydrous manganese arsenate with formula: Mn5(AsO3OH)2(AsO4)2·10H2O. It forms triclinic pinacoidal, vitreous, colorless to red to brown crystals. It has a Mohs hardness of 3 and a specific gravity of 3.05.

Campigliaite is a copper and manganese sulfate mineral with a chemical formula of Cu4Mn(SO4)2(OH)6·4H2O. It has a chemical formula and also a crystal structure similar to niedermayrite, with Cd(II) cation replacing by Mn(II). The formation of campigliaite is related to the oxidation of sulfide minerals to form sulfate solutions with ilvaite associated with the presence of manganese. Campigliaite is a rare secondary mineral formed when metallic sulfide skarn deposits are oxidized. While there are several related associations, there is no abundant source for this mineral due to its rare process of formation. Based on its crystallographic data and chemical formula, campigliaite is placed in the devillite group and considered the manganese analogue of devillite. Campigliaite belongs to the copper oxysalt minerals as well followed by the subgroup M=M-T sheets. The infinite sheet structures that campigliaite has are characterized by strongly bonded polyhedral sheets, which are linked in the third dimension by weaker hydrogen bonds.

<span class="mw-page-title-main">Wakefieldite-(La)</span>

Wakefieldite-(La) is the lanthanum analogue of the uncommon rare-earth element vanadate mineral Wakefieldite. It is a member of the xenotime group.

Wakefieldite-(Nd) is the neodymium analogue of the uncommon rare-earth element vanadate mineral wakefieldite. It is a member of the xenotime group.

<span class="mw-page-title-main">Shigaite</span>

Shigaite is a mineral with formula NaAl3(Mn2+)6(SO4)2(OH)18·12H2O that typically occurs as small, hexagonal crystals or thin coatings. It is named for Shiga Prefecture, Japan, where it was discovered in 1985. The formula was significantly revised in 1996, identifying sodium as a previously unknown constituent.

Gatehouseite is a manganese hydroxy phosphate mineral with formula Mn5(PO4)2(OH)4. First discovered in 1987, it was identified as a new mineral species in 1992 and named for Bryan M. K. C. Gatehouse (born 1932). As of 2012, it is known from only one mine in South Australia.

<span class="mw-page-title-main">Sonolite</span>

Sonolite is a mineral with formula Mn9(SiO4)4(OH,F)2. The mineral was discovered in 1960 in the Sono mine in Kyoto Prefecture, Japan. In 1963, it was identified as a new mineral and named after the Sono mine.

<span class="mw-page-title-main">Manganvesuvianite</span>

Manganvesuvianite is a rare mineral with formula Ca19Mn3+(Al,Mn3+,Fe3+)10(Mg,Mn2+)2(Si2O7)4(SiO4)10O(OH)9. The mineral is red to nearly black in color. Discovered in South Africa and described in 2002, it was so named for the prevalence of manganese in its composition and its relation to vesuvianite.

<span class="mw-page-title-main">Hollandite</span>

Hollandite (chemical formula: Ba(Mn4+6Mn3+2)O16) is an oxide mineral. It is the barium-manganese (III) endmember of the coronadite group.

<span class="mw-page-title-main">Gurimite</span> Barium vanadate mineral

Gurimite is a rare mineral with formula Ba3(VO4)2. It is a simple barium vanadate, one of the most simple barium minerals known. It is named after its type locality - Gurim anticline in Israel. It has formed in the rocks of the Hatrurim Formation. Gurimite's stoichiometry is similar to that of copper vanadates mcbirneyite and pseudolyonsite. An example of other barium vanadate mineral is tokyoite.

Iyoite is a very rare manganese copper chloride hydroxide mineral with the formula MnCuCl(OH)3. Iyoite is a new member of the atacamite group, and it an analogue of botallackite characterized in manganese and copper ordering. Iyoite is monoclinic (space group P21/m). It is chemically similar to misakiite. Both minerals come from the Ohku mine in the Ehime prefecture, Japan.

<span class="mw-page-title-main">Jinshajiangite</span>

Jinshajiangite is a rare silicate mineral named after the Jinshajiang river in China. Its currently accepted formula is BaNaFe4Ti2(Si2O7)2O2(OH)2F. It gives a name of the jinshajiangite group. The mineral is associated with alkaline rocks. In jinshajiangite, there is a potassium-to-barium, calcium-to-sodium, manganese-to-iron and iron-to-titanium diadochy substitution. Jinshajiangite is the iron-analogue of surkhobite and perraultite. It is chemically related to bafertisite, cámaraite and emmerichite. Its structure is related to that of bafertisite. Jinshajiangite is a titanosilicate with heteropolyhedral HOH layers, where the H-layer is a mixed tetrahedral-octahedral layer, and the O-layer is simply octahedral.

Fluorcarmoite-(BaNa) is a rare phosphate mineral, belonging to arrojadite group, with the formula Ba[]Na2Na2[]CaMg13Al(PO4)11(PO3OH)F2. It is a barium-rich member of the group, as is arrojadite-(BaNa), arrojadite-(BaFe), fluorarrojadite-(BaFe) and an unapproved species ferri-arrojadite-(BaNa). The "-(BaNa)" suffix informs about the dominance of the particular elements (here barium and sodium) at the corresponding structural sites.

Manganiceladonite is a rare silicate mineral with the formula KMgMn3+Si4O10(OH)2. It is one of many minerals discovered in the Cerchiara mine, La Spezia, Liguria, Italy.

<span class="mw-page-title-main">Gottlobite</span>

Gottlobite, CaMg(VO4,AsO4)(OH), is a mineral found as isolated crystals or isometric grains of orange or orange-brown color. The size of the crystals are a half millimeter in diameter and are part of the orthorhombic crystal system. Gottlobite forms a solid solution with adelite, which is an end member composition of CaMg(VO4)(OH), as well as being classified in the adelite group. Gottlobite is also part of the vanadates and arsenates group. With these characteristics, it is similar to the minerals tangeite and austinite by X-ray diffraction methods.

Ganophyllite is a phyllosilicate mineral. It was named by Axel Hamberg in 1890 from the Greek words for leaf (φύλλον) and luster (γανωμα); the latter one was chosen due to the lustrous cleavages. The mineral was approved by the IMA in 1959, and it is a grandfathered mineral, meaning its name is still believed to refer to an existing species until this day. Tamaite is the calcium analogue, while eggletonite is the natrium analogue of said mineral.

Fianelite is a mineral belonging to the manganese vanadate category, found in iron-manganese ores. Named after the place where it was found, Fianel, a mine located in Val Ferrera, in the canton of Graubünden, Swiss. This mineral is found in small amounts in metamorphosed iron-manganese ores. This is the last crystallization of vanadate at the site since medaite was the last vanadate mineral being crystallized, but because of retrograde metamorphism, occurring at the place, vanadium moved into medaite veinlets, forming cross-cutting fianelite on medaite.


  1. Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi: 10.1180/mgm.2021.43 . S2CID   235729616.
  2. 1 2 3 Mindat
  3. 1 2 3 Webmineral data
  4. 1 2 3 Matsubara, Satoshi, et al., Tokyoite, Ba2Mn3+(VO4)2(OH), a new mineral from the Shiromaru mine, Journal of Mineralogical and Petrological Sciences, V. 99, pp. 363-7, 2004