Fragrance

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Fragrance
Duftite-107517.jpg
Grape fragrance aggregate from the Sanyati mine, Kadoma , Zimbabwe (field of view 4 mm)
General and classification
chemical formula PbCu 2+ [OH | AsO 4 ]
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.BH.35 ( 8th edition : VII / B.26)
41.05.01.04 (Duftit-beta) or 41.05.02.05 (Duftit-alpha)
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-disphenoidic; 222
Space group P 2 1 2 1 2 1 (No. 19)Template: room group / 19
Lattice parameters a  = 7.768  Å ; b  = 9.211 Å; c  = 5.999 Å
Formula units Z  = 4
Physical Properties
Mohs hardness 3
Density (g / cm 3 ) 6.4 to 6.6
Cleavage indistinct
Break ; Tenacity uneven
colour gray green, olive green, apple green
Line color greenish white
transparency translucent
shine Glass gloss, matt
Crystal optics
Refractive indices n α  = 2.040
n β  = 2.080
n γ  = 2.100
Birefringence δ = 0.060
Optical character biaxial negative

Fragrance is a rarely occurring mineral from the mineral class of "phosphates, arsenates and vanadates". It crystallizes in the orthorhombic crystal system with the chemical composition PbCu [OH | AsO 4 ] and is thus a lead - copper - arsenate with additional hydroxide .

Fragrance is mostly found in the form of grape mineral aggregates or crusty coatings, but also develops small, millimeter-sized crystals of gray-green, olive-green or apple-green color. The crystals are translucent and have a glass-like sheen on the surface .

Etymology and history

Fragrance on calcite from Tsumeb, Namibia - exhibited in the Essen-Kupferdreh mineral museum

Fragrance was first discovered in the Tsumeb Mine in Namibia and described in 1920 by Otto Hermann August Pufahl (1855–1924). He named the mineral after Gustav Duft, the manager of the Otavi Mine near Tsumeb at the time.

classification

Even in the outdated, but partly still in use 8th edition of the mineral classification according to Strunz , the fragrance belonged to the mineral class of "phosphates, arsenates and vanadates" and there to the department of "anhydrous phosphates, with foreign anions F, Cl, O, OH", where, together with Adelite , Austinite , Gabrielsonite , Gottlobit , Cobaltaustinite , Konichalcite , Nickelaustinite and Tangeit, he created the "Adelite Group" with the system no. VII / B.26 .

The 9th edition of Strunz's mineral systematics , which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), also assigns the fragrance to the category of “phosphates etc. with additional anions; without H 2 O “. However, this is further subdivided according to the relative size of the cations involved and the molar ratio of the additional anions (OH, etc.) to the phosphate, arsenate or vanadate complex RO 4 , so that the mineral is classified according to its composition in the subsection “With medium-sized and mostly large cations; (OH etc.): RO 4  = 1: 1 “can be found where, together with Adelite, Arsendescloizit, Austinite, Cobaltaustinite, Gabrielsonite, Gottlobit, Konichalcite, Nickelaustinite and Tangeit, the“ Adelite group ”with the system no. 8.BH.35 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the fragrance to the class of "phosphates, arsenates and vanadates" and there in the category of "anhydrous phosphates etc., with hydroxyl or halogen". Here he is the only member / together with the " Adelit group " with the system no. 41.05.01 to be found in the subsection “Anhydrous phosphates etc., with hydroxyl or halogen with (AB) 2 (XO 4 ) Z q ”.

Crystal structure

Fragrance crystallizes in the orthorhombic crystal system in the space group P 2 1 2 1 2 1 (space group no. 19) with the lattice parameters a = 7.768  Å , b = 9.211 Å and c = 5.999 Å as well as four formula units per unit cell . Template: room group / 19

Education and Locations

Needle fragrance, crystal size approx. 1 to 2 mm from the Clara mine , Germany

Fragrance forms as a secondary mineral in copper deposits . Accompanying minerals are mainly azurite , malachite and other secondary copper minerals, but also bayldonite , beudantite , calcite , cerussite , mimetesite , mottramite , olivite and wulfenite .

In addition to its type locality Tsumeb, Duftite was found in Namibia on the Kupferberg mountain pass and in the Kombat Mine near Grootfontein .

So far (as of 2009) the following sites have been registered for the mineral worldwide: Córdoba in Argentina; New South Wales , Northern Territory , South Australia and Western Australia in Australia; Región de Atacama in Chile; Baden-Württemberg (Black Forest), Bavaria (Spessart), Hesse (Odenwald), Lower Saxony (Harz), North Rhine-Westphalia (Bergisches Land), Rhineland-Palatinate and Saxony (Ore Mountains) in Germany; different regions in France ; at Laurion in Greece; England and Scotland in Great Britain; Piedmont , Sardinia and Tuscany in Italy; Kyushu in Japan; Durango in Mexico; Carinthia and Tyrol in Austria; Lower Silesia (Měděnec) in Poland; Beja District (Cerro do Algaré Mine) in Portugal; Andalusia in Spain; Glarus , Graubünden and Valais in Switzerland; Gauteng in South Africa; Bohemia in the Czech Republic; Urals in Russia; several regions of the US ; as well as Mashonaland in Zimbabwe.

See also

literature

Web links

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

Individual evidence

  1. ↑ a b c American Mineralogist Crystal Structure Database - Duftite (English, 1998)
  2. ↑ a b Webmineral - Duftite-beta (English)
  3. ↑ a b Webmineral - Duftite-alpha (English)
  4. ↑ a b c d Duftite at mindat.org (English)
  5. ↑ “Duftit” profile at steine-und-minerale.de
  6. ^ Locations for Duftit in the Mineralienatlas and Mindat