Triplite

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Triplite
Triplite-t5105a.jpg
General and classification
chemical formula
  • (Mn, Fe) 2 [F | PO 4 ]
  • (Mn 2+ , Fe 2+ ) 2 (PO 4 ) F.
Mineral class
(and possibly department) 		Phosphates, arsenates and vanadates
System no. to Strunz
and to Dana 		8.BB.10 ( 8th edition : VII / B.03)
06.41.01.02
Similar minerals Rhodochrosite , rhodonite
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group I 2 / a (No. 15, position 3)Template: room group / 15.3
Lattice parameters a  = 12.06  Å ; b  = 6.45 Å; c  = 9.94 Å
β  = 107.1 °
Formula units Z  = 8
Physical Properties
Mohs hardness 5 to 5.5
Density (g / cm 3 ) measured: 3.5 to 3.9; calculated: 3.85 to 3.94
Cleavage good after {001}, clear after {010}, indistinct after {100}
Break ; Tenacity uneven to scalloped
colour brown to brownish black, salmon pink
Line color white to light brown
transparency translucent to opaque
shine Glass gloss to fat gloss
Crystal optics
Refractive indices n α  = 1.650
n β  = 1.660
n γ  = 1.680
Birefringence δ = 0.030
Optical character biaxial positive
Axis angle 2V = 70 to 90 °

Triplite , as Eisenpecherz or iron apatite known, a rarely occurring minerals from the mineral class of "phosphates, arsenates, and vanadates" with the chemical composition of (Mn, Fe) 2 [F | PO 4 ] and chemical point of view, a manganese - iron - Phosphate with additional fluorine ions . The elements manganese and iron indicated in the round brackets can represent each other in the formula ( substitution , diadochie), but are always in the same proportion to the other components of the mineral.

Triplite crystallizes in the monoclinic crystal system and develops mostly opaque, granular to massive aggregates that reach sizes of several meters at some sites. Translucent, short-prismatic crystals are rarely found . The color varies between brown to brownish black and salmon pink.

Triplite forms a mixed series with zwieselite ((Fe, Mn) 2 [F | PO 4 ]).

Etymology and history

Was first found in 1813 in Triplite Chanteloube in the town of Razès in the French department of Haute-Vienne and described by Hausmann , of the mineral on the basis of the three cleavage directions after the Greek word τριπλόος [tri'ploʔos] for three times named.

classification

In the now outdated 8th edition of the mineral classification according to Strunz , the triplite belongs to the division of "anhydrous phosphates with foreign anions ", where together with magniotriplite , sarkinite , staněkite , triploidite , wagnerite and the eponymous minerals Wolfeit and Zwieselite, it forms the "Zwieselite-Wolfeit -Group "forms.

Since the revision of Strunz's mineral systematics in the 9th edition of the mineral systematics according to Strunz , this section has been more precisely subdivided according to the size of the cations involved and the molar ratio of the anions involved and the phosphate, arsenate or vanadate complex and the mineral is accordingly in the subdivision “With only medium-sized cations; (OH etc.): RO 4  ≥ 1: 1 “to be found. The original mineral group was also further subdivided and the unnamed group 8.BB.10 consists of triplite and only hydroxylwagnerite and zwieselite.

The systematics of minerals according to Dana also sorts the triplite into the class of phosphates, but there into the division of " anhydrous phosphates etc. with hydroxyl or halogen and the general formula (A) 2 (XO 4 ) Z q ". The unnamed group 41.06.01 consists of triplite, zwieselite and magniotriplite .

Crystal structure

Triplite crystallizes monoclinically in the space group I 2 / a (space group no. 15, position 3) with the lattice parameters a  = 12.06  Å ; b  = 6.45 Å; c  = 9.94 Å and β = 107.1 ° and 8 formula units per unit cell . Template: room group / 15.3

Education and Locations

Pink triplite surrounded by gray quartz. On the right edge of the picture is a black diabase passage next to cream-colored albite

Triplite forms as a primary - phosphate -mineral in granites or pegmatite , but can also by hydrothermal processes in the aged and quartz - transitions occur. Accompanying minerals include albite , apatite , lithiophilite , phosphosiderite , pyrite , quartz, sphalerite , triphyline , triploidite , tourmaline , vivianite , wolfite and ore minerals such as spodumene , amblygonite , cassiterite and tantalite (Mn) .

Triplite has been detected at around 120 sites around the world so far (as of 2010), including in the states and regions of Argentina , Australia , Bolivia , Brazil , China , Germany , Finland , France , Italy , Canada , Madagascar , Mozambique , Namibia , North Korea , Norway , Austria , Pakistan , Poland , Portugal , Rwanda , Russia , Sweden , Switzerland , Zimbabwe , South Africa , Czech Republic , United Kingdom (Great Britain), United States (USA).

The Karibib region in Namibia is known for its massive triplite aggregates, which are several meters in size .

use

Salmon red triplite in "Ceylon" cut

Triplite is too seldom found in the appropriate quality for commercial use as a gemstone , but is occasionally offered in various facet cuts and is particularly valuable as a rarity , especially among collectors .

See also

literature

Web links

Commons : Triplite  - collection of images, videos and audio files

Individual evidence

  1. ↑ a b c d e f Hugo Strunz , Ernest H. Nickel : Strunz Mineralogical Tables. Chemical-structural Mineral Classification System . 9th edition. E. Schweizerbart'sche Verlagbuchhandlung (Nägele and Obermiller), Stuttgart 2001, ISBN 3-510-65188-X , p.  442 .
  2. ^ IMA / CNMNC List of Mineral Names; September 2016 (English, PDF 1.6 MB, p. 185)
  3. ↑ Webmineral - Triplite (English)
  4. ↑ a b c Triplite , In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America , 2001 ( PDF 65.5 kB )
  5. ↑ a b c d e Triplite at mindat.org (engl.)
  6. ↑ Find location list for triplite in the Mineralienatlas and Mindat
  7. ↑ realgems.org - triplite with image examples of cut stones