Libethenite

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Libethenite
Libethenite-tuc1033b.jpg
Libethenite crystals from Kambove ( Katanga Province ), Congo
General and classification
chemical formula Cu 2 [OH | PO 4 ]
Mineral class
(and possibly department) 		Phosphates, arsenates, vanadates
System no. to Strunz
and to Dana 		8.BB.30 ( 8th edition : VII / B.06)
41.06.06.02
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal 2 / m 2 / m 2 / m
Space group Pnnm
Lattice parameters a  = 8.062  Å ; b  = 8.384 Å; c  = 5.881 Å
Formula units Z  = 4
Frequent crystal faces {110}, {011}, {111}
Physical Properties
Mohs hardness 4th
Density (g / cm 3 ) 3.6 to 4
Cleavage indistinct after {100} and {010}
Break ; Tenacity shell-like to uneven
colour light green to greenish black
Line color green to greenish white
transparency translucent
shine Greasy shine
Crystal optics
Refractive indices n α  = 1.701 to 1.704
n β  = 1.743 to 1.747
n γ  = 1.787 to 1.790
Birefringence δ = 0.086
Optical character biaxial negative
Axis angle 2V = 80 to 90 °

Libethenite ( leafy olive ore ) is a rather seldom occurring mineral from the mineral class of " phosphates , arsenates and vanadates ". It crystallizes in the orthorhombic crystal system with the chemical composition Cu 2 [OH | PO 4 ] and develops mostly short prismatic, needle-like or dipyramidal crystals , but also grape, kidney or granular to massive mineral aggregates of light green to greenish black and green to greenish white line color.

With adamin and olivenite, libethenite forms an isomorphic mixed series named after him , which is also isotypic to andalusite , i.e. crystallizes in the same crystal structure .

Etymology and history

Libethenite was found for the first time in 1823 in Ľubietová (German Libethen, Slovakia ) and described by Johann Friedrich August Breithaupt , who named the mineral after this type of locality .

classification

In the meantime outdated classification of minerals by Strunz (8th edition) of Libethenit is part of the department of "water clear phosphates with foreign anions " and forms there together with Adamin, Eveit , Olivenit, Paradamin , Tarbuttit and Zincolibethenit the Libethenit series .

Since the revision of Strunz's mineral classification in the 9th edition , this section has also 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 subsection " With only medium-sized cations; (OH etc.): RO 4  ≥ 1: 1 “to be found.

The systematics of minerals according to Dana sorts the libethenite into the division of " anhydrous phosphates etc. with hydroxyl or halogen and the general formula (A) 2 (XO 4 ) Z q ".

Education and Locations

Macro shot of perfect libethenite single crystal on light blue zapatalite
Same crystal, top view

Libethenit forms as a secondary mineral in the oxidation zone of copper - deposits and there occurs predominantly in Paragenesis with azurite , malachite , Pseudomalachit , chrysocolla , and various iron oxides either singly or grown in drusen on.

In Germany, the mineral has so far been found in the Black Forest , Upper Palatinate Forest , Northern Hesse and Odenwald , Eifel and Westerwald , near Düppenweiler , Ore Mountains , as well as near Bad Lobenstein and in Vogtland .

To date, libethenite has been detected at around 180 sites worldwide (as of 2009), including at Cerro Blanco in Argentina; several regions of Australia ; in Vielsalm , Belgium ; several regions of Chile ; in several regions of England ; in some French regions; Liguria and Sardinia in Italy; on Honshū in Japan; in the Katanga province of the Democratic Republic of the Congo (formerly the Belgian Congo and Zaïre); in the pool region of the neighboring state of the Republic of the Congo (formerly French Congo) Durango and Sonora in Mexico; in some regions of Portugal ; in the regions of Eastern Siberia and the Urals of Russia; near Banská Bystrica in Slovakia; the Spanish regions of Aragon , Castile-La Mancha and Catalonia ; Mpumalanga and the North Cape in South Africa; near Karlsbad in the Czech Republic; as well as in many regions of the United States .

Synthetic manufacture

Libethenite is obtained by heating copper phosphate Cu 3 P 2 O 8 + 3H 2 O with water in sealed tubes.

Crystal structure

Crystal structure of libethenite.
Red and orange: copper; Yellow: phosphorus, blue: oxygen, gray: hydrogen

Libethenite crystallizes orthorhombically in the space group Pnnm with the lattice parameters a  = 8.062  Å ; b  = 8.384 Å and b  = 5.881 Å as well as four formula units per unit cell .

See also

Individual evidence

  1. ↑ a b c d Webmineral
  2. ↑ a b c Libethenite at mindat.org (engl.)
  3. ↑ Stefan Weiß: The large Lapis mineral directory . 5th edition. Christian Weise Verlag, Munich 2008, ISBN 3-921656-17-6 .
  4. ^ Paul Ramdohr , Hugo Strunz : Klockmanns textbook of mineralogy . 16th edition. Ferdinand Enke Verlag, 1978, ISBN 3-432-82986-8 , pp. 629 .
  5. ↑ Mindat - Localities for Libethenit
  6. ^ Meyers Konversationslexikon Libethenit

literature

  • Petr Korbel, Milan Novák: Encyclopedia of Minerals . Nebel Verlag GmbH, Eggolsheim 2002, ISBN 3-89555-076-0 , p. 160 .

Web links

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