Pseudorutile

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Pseudorutile
General and classification
chemical formula Fe 2 3+ Ti 3 4+ O 9
Mineral class
(and possibly department) 		Oxides and hydroxides
System no. to Strunz
and to Dana 		4.CB.25 ( 8th edition : IV / C.24)
04/08/02/01
Crystallographic Data
Crystal system hexagonal
Crystal class ; symbol hexagonal trapezoidal; 622
Space group P 6 3 22
Lattice parameters a  = 14.375  Å ; c  = 4.615 Å
Formula units Z  = 5
Physical Properties
Mohs hardness 3.5
Density (g / cm 3 ) measured: approx. 3.8; calculated: 4.82
Cleavage is missing
Break ; Tenacity shell-like
colour black, brown, gray-red
Line color reddish brown
transparency opaque, transparent in very thin layers
shine Metallic luster
Other properties
Special features magnetic

Pseudorutil is a rarely occurring mineral from the mineral class of " oxides and hydroxides ". It crystallizes in the hexagonal crystal system with the chemical composition Fe 2 3+ Ti 3 4+ O 9 and develops platy or leafy to fibrous crystals , but also granular to massive mineral aggregates of black, brown or gray-red color and reddish-brown line color .


Etymology and history

Pseudorutil was first found in 1966 south of Neptune Island in South Australia (Australia) and described by G. Teufer and AK Temple. Due to its similarity to rutile and thus its likelihood of confusion, it was named after it with the addition of the Greek root word ψευδώ [pseudó] for false, fake or pretended.

classification

In the old systematics of minerals according to Strunz (8th edition) the pseudorutile belonged to the department of "oxides with the molar ratio metal: oxygen = 2: 3", where it forms a separate, unnamed group together with armalcolite and pseudobrookite .

Since the 9th edition of Strunz's mineral systematics , the departments of the oxide / hydroxide class have been subdivided more precisely according to the size of the cations and some have been renamed. Pseudorutile is now in the subdivision of "Oxides with the molar ratio metal: oxygen = 2: 3, 3: 5 and comparable and medium-sized cations", where it is the only member of the unnamed group 4.CB.25 .

The systematics of minerals according to Dana , which is common in the English-speaking world , also sorts the pseudorutile into the class of oxides and hydroxides, but there into the division of " multiple oxides with Nb, Ta and Ti with various formulas ", where he is the only member of the unnamed subdivision 04/08/02 forms.

Education and Locations

Pseudorutile forms secondarily as a metastable intermediate link during the weathering of ilmenite . In addition to ilmenite, accompanying minerals are therefore rutile, anatase , hematite and gadolinite .

In addition to its type locality Neptune Island, pseudorutil could also be found in Australia at Carapooee , at Lake Boga and at St Arnaud in the state of Victoria . So far (as of 2010) the mineral has been detected at around 20 sites worldwide: near Algiers in Algeria; in Prydz Bay in East Antarctica; near Bitterfeld (Saxony-Anhalt) and near Borna , Chemnitz , Freiberg and Mittweida (Saxony) in Germany; at Nkambé in Cameroon ; near Montreal in Canada; in Fulpmes , Austria ; in Tambov Oblast in Russia; in the Namakwa sand pit in South Africa; in Czech Bohemia as well as in Park County (Colorado) , Florida , near Lakehurst (New Jersey) and near Baraboo in Sauk County (Wisconsin) in the USA .

Crystal structure

Pseudorutile crystallizes hexagonally in the space group P 6 3 22 with the lattice parameters a  = 14.375  Å and c  = 4.615 Å as well as five formula units per unit cell .

See also

Individual evidence

  1. ↑ a b c American Mineralogist Crystal Structure Database - Pseudorutile , 1975 (English)
  2. ^ A b c Hugo Strunz , Ernest H. Nickel: Strunz Mineralogical Tables . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p. 195 .
  3. ↑ Handbook of Mineralogy - Pseudorutile (English; PDF; 69.5 kB)
  4. ↑ Localities for Pseudorutile , Mindat

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