Delindeit

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Delindeit
Delindeite-107200.jpg
About 1.5 mm long prismatic Delindeite crystal from Yukspor, Chibinen, Kola, Russia
General and classification
other names

IMA 1987-004

chemical formula
  • Ba 2 Na 2 Ti 3 (Si 2 O 7 ) 2 O 2 (OH) 2 · 2H 2 O
  • (Na, K) 3 (Ba, Ca) 4 (Ti, Fe, Al) 6 H 2 [(OH) 3 | Si 2 O 7 ] 4
Mineral class
(and possibly department) 		Silicates and germanates - group silicates (sorosilicates)
System no. to Strunz
and to Dana 		9.BE.60 ( 8th edition : VIII / C.15)
56.02.06c.02
Crystallographic Data
Crystal system monoclinic
Crystal class ; symbol monoclinic prismatic; 2 / m
Space group C 2 / c (No. 15)Template: room group / 15
Lattice parameters a  = 10.6452 (9)  Å ; b  = 13.713 (1) Å; c  = 21.600 (2) Å
β  = 93.804 (3) °°
Formula units Z  = 8
Twinning submicroscopic after {100}
Physical Properties
Mohs hardness Please complete!
Density (g / cm 3 ) measured: 3.3 (1); calculated: 3.70 (1)
Cleavage good after {001}
Break ; Tenacity uneven; brittle
colour light pink gray
Line color White
transparency translucent
shine Resin luster, pearlescent luster
Crystal optics
Refractive indices n α  = 1.790
n β  = 1.825
n γ  = 1.982
Birefringence δ = 0.192
Optical character biaxial positive
Axis angle 2V = measured and calculated 54 °

Delindeite is a very rarely occurring mineral from the mineral class of "silicates and germanates" with the chemical composition Ba 2 Na 2 Ti 3 (Si 2 O 7 ) 2 O 2 (OH) 2 · 2H 2 O and thus chemically a water-containing barium - Sodium - titanium - silicate with additional hydroxide ions . Structurally, Delindeite belongs to the group silicates (sorosilicates).

Delindeit crystallizes in the monoclinic crystal system and develops mostly spherulitic mineral aggregates , consisting of lath or strip-shaped crystals or flakes of up to one millimeter in size. The translucent crystals are light pink-gray in color and have a resin-like to mother-of-pearl-like sheen on the surface .

Etymology and history

Delindeit was discovered for the first time together with Lourenswalsit in the "Diamond Jo" quarry at the Magnet Cove Complex in Hot Spring County in the US state of Arkansas . The mineral was described by Daniel E. Appleman, Howard T. Evans (Jr.), Gordon L. Nord, Edward J. Dwornik and Charles Milton, who named it after the owner of the quarry, Henry S. deLinde.

classification

Already in the outdated, but partly still in use 8th edition of the mineral systematics according to Strunz , Delindeit belonged to the mineral class of "silicates and Germanates" and there to the department of "group silicates (sorosilicates)", where he together with Bafertisit , Fresnoit , Hejtmanit and Nechelyustovit die "Bafertisit series" with the system no. VIII / C.15 formed.

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 classifies the Delindeit in the group of "group silicates". However, this is further subdivided according to the structure of the silicate groups, the possible presence of additional anions and the coordination of the cations involved . According to its structure, the mineral is therefore in the subsection “Si 2 O 7 groups with additional anions; Cations are found in octahedral [6] and greater coordination ”, where it is the only member of the unnamed group 9.BE.60 .

The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns the Delindeit to the class of "silicates and Germanates" in the department of "group silicates". Here it is together with Barytolamprophyllit , Ericssonite , Lamprophyllit , Orthoericssonit , Andrémeyerit , Eveslogit and Nabalamprophyllit in the " Seidozerit-Lamprophyllit group (Lamprophyllit subgroup) " with the system number. 56.02.06c within the subsection “Group silicates: Si 2 O 7 groups and O, OH, F and H 2 O with cations in [4] and / or> [4] coordination”.

Crystal structure

Delindeit crystallizes monoclinically in the space group C 2 / c (space group no. 15) with the lattice parameters a  = 10.6452 (9)  Å ; b  = 13.713 (1) Å; c  = 21.600 (2) Å and β = 93.804 (3) ° and 8 formula units per unit cell . Template: room group / 15

Education and Locations

Delindeit, benitoite (blue) and joaquinite (Ce) (black in the background) from the California State gem mine on the San Benito River, California, USA (field of view 1.9 cm)

The quarry "Diamond Jo" in which the Delindeit was found there, from garnet -Pseudo Leucit - syenites in an alkaline Ring Dyke complex of nepheline -Syenit, pegmatite , Ijolith and carbonatite . Delindeit formed there in geodes and miarolitic cavities as the weathering product of titanium-containing nepheline syenites. In addition to lourenswalsite, pectolite , barite , labuntsovite , titanite , sphalerite as well as pyroxene and potassium-containing feldspars appeared as accompanying minerals .

In addition to its type locality "Diamond Jo" in Arkansas, the mineral could so far only be found in the USA (as of 2016) in the California State gem mine on the San Benito River in the county of the same name in the state of California .

The only other sites are on Yukspor and Kukiswumtschorr in the Chibinen on the Russian Kola Peninsula .

See also

literature

  • Daniel E. Appleman, Howard T. Evans (Jr.), Gordon L. Nord, Edward J. Dwornik, Charles Milton: Delindeite and lourenswalsite, two new titanosilicates from the Magnet Cove region, Arkansas . In: Mineralogical Magazine . tape 51 , 1987, pp. 417-425 ( rruff.info [PDF; 744 kB ]).
  • Giovanni Ferraris, Gabriella Ivaldi, Dmitry Yu. Pushcharovsky, Natalia. V. Zubkova, Igor V. Pekov: The crystal structure of delindeite, Ba 2 {(Na, K, □) 3 (Ti, Fe) [Ti 2 (O, OH) 4 Si 4 O 14 ] (H 2 O, OH) 2 }, a member of the mero-plesiotype bafertisite series . In: The Canadian Mineralogist . tape 39 , 2001, ISSN  0008-4476 , p. 1307-1316 ( rruff.info [PDF; 923 kB ]).

Web links

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

Individual evidence

  1. ↑ a b c d e Elena Sokolova, Fernando Cámara: From structure topology to chemical composition. II. Titanium silicates: Revision of the crystal structure and chemical formula of Delindeite . In: The Canadian Mineralogist . tape 45 , 2007, p. 1247–1261 , doi : 10.2113 / gscanmin.45.5.1247 ( rruff.info [PDF; 579 kB ]).
  2. ^ 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.  581 .
  3. ↑ a b Webmineral - Delindeite
  4. ↑ a b c d Delindeite. In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America. 2001 (PDF)
  5. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties . 6th, completely reworked and supplemented edition. Weise, Munich 2014, ISBN 978-3-921656-80-8 .
  6. ↑ a b c d e Mindat - Delindeite
  7. ↑ Find location list for Delindeit at the Mineralienatlas and at Mindat