Lavinskyite

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Lavinskyite
Lavinskyite-482945.jpg
Lavinskyite from the Wessels Mine, Hotazel , Kalahari Manganese Fields, North Cape Province, South Africa ( overall size : 3 cm × 2 cm × 1.7 cm)
General and classification
other names

IMA 2012-028

chemical formula K (Li, Cu) Cu 6 [(OH) 2 | Si 4 O 11 ] 2
Mineral class
(and possibly department) 		Silicates and Germanates
Crystallographic Data
Crystal system orthorhombic
Crystal class ; symbol orthorhombic-dipyramidal; 2 / m  2 / m  2 / m
Space group Pcnb (No. 60, position 6)Template: room group / 60.6
Lattice parameters a  = 19.046 (2)  Å ; b  = 20.377 (2) Å; c  = 5.2497 (6) Å
Formula units Z  = 4
Physical Properties
Mohs hardness 5
Density (g / cm 3 ) measured: 3.61 (3); calculated: 3.62
Cleavage completely after {010}
Break ; Tenacity brittle
colour Light Blue
Line color pale blue
transparency transparent
shine Glass gloss
Crystal optics
Refractive indices n α  = 1.675 (1)
n β  = 1.686 (1)
n γ  = 1.715 (1)
Optical character biaxial positive
Axis angle 2V = 64 (2) °

Lavinskyite is a very rarely occurring mineral from the mineral class of " silicates and germanates ". It crystallizes in the orthorhombic crystal system with the chemical composition K (Li, Cu) Cu 6 [(OH) 2 | Si 4 O 11 ] 2 and is chemically a potassium - copper- silicate with additional hydroxide ions . Since in natural Lavinskyite samples, however, part of the copper is always represented ( substituted ) by lithium , these two elements are separated from the rest of the formula by round brackets, but this proportion is always in the same proportion to the other components of the mineral.

Lavinskyite is transparent and develops light blue, tabular crystals with a glass-like sheen on the surfaces.

Etymology and history

Lavinskyite was discovered in the Wessels Mine near Hotazel in the manganese deposit of the Kalahari in South Africa and described in 2012 by Hexiong Yang, Robert T. Downs, Stanley H. Evans, William W. Pinch and Marcus J. Origlieri. The mineral was named after the mineral collector and owner of the mineral trading company "The Arkenstone" Robert Matthew "Rob" Lavinsky (* 1972).

Type material of the mineral is kept in the Mineral Museum of the University of Arizona (Catalog No. 19335) and in the "RRUFF Project" (File R120057). The holotype material belongs to the collection of William W. Pinch.

classification

Lavinskyite was only recognized and published as an independent mineral by the International Mineralogical Association (IMA) in 2012 . An exact group assignment in the 9th edition of the Strunz'schen mineral systematics , the last update of which was carried out with the publication of the IMA list of mineral names in 2009, is therefore not yet known.

Due to its structural relationship with planchite and shattuckite , Lavinskyite is presumably also included in the chain and band silicates department and there in the chain and band silicates with 2-periodic single chains Si 2 O 6 ; with additionally O, OH, H 2 O; Pyroxene-related minerals (system no. 9.DB. ) classified.

Crystal structure

Lavinskyite crystallizes isotypically with plancheit in the orthorhombic crystal system in the space group Pcnb (space group no. 60, position 6) with the lattice parameters a  = 19.046 (2)  Å ; b  = 20.377 (2) Å and c  = 5.2497 Å as well as formula units per unit cell . Template: room group / 60.6

Education and Locations

The only known site of Lavinskyite is its type locality Wessels Mine in the South African Kalahari, where it occurs in association with the minerals wesselsite and scottyite, which were also first discovered there ( IMA 2012-027 ) as well as with pectolite , Richterite and sugilite .

The "N'Chwaning II" pit near Kuruman is mentioned as a further location , but the find has not yet been confirmed.

See also

literature

  • PA Williams, F. Hatert, M. Pasero, SJ Mills: IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) Newsletter 14, New minerals and nomenclature modifications approved in 2012. In: Mineralogical Magazine Volume 76 (2012), pp. 1281–1288 ( PDF 93.2 kB )
  • Hexiong Yang, Robert T. Downs, Stanley H. Evans, William W. Pinch: Lavinskyite, K (Li, Cu) Cu 6 (Si 4 O 11 ) 2 (OH) 4 , isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa. In: American Mineralogist Volume 99 (2014), pp. 525-530 ( PDF 1.85 MB )

Web links

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

Individual evidence

  1. ↑ a b Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th completely revised and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  2. ↑ a b c d e f g h i Hexiong Yang, Robert T. Downs, Stanley H. Evans, William W. Pinch: Lavinskyite, K (Li, Cu) Cu 6 (Si 4 O 11 ) 2 (OH) 4 , isotypic with plancheite, a new mineral from the Wessels mine, Kalahari Manganese Fields, South Africa. In: American Mineralogist Volume 99 (2014), pp. 525-530 ( PDF 1.85 MB )
  3. ^ The Mineralogical Record - Rob Lavinsky
  4. ↑ IMA / CNMNC List of Mineral Names September 2009 (PDF 1.8 MB with the last official Strunz classification)
  5. ^ Mindat - Lavinskyite
  6. ^ Mindat - type locality Wessels Mine, Hotazel, Kalahari manganese field, Northern Cape Province, South Africa