Calcioburbankite

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Calcioburbankite
General and classification
other names
  • IMA 1993-001
  • MSH UK-100A
chemical formula
  • Na 3 (Ca, REE, Sr) 3 (CO3) 5
  • Na 3 (Ca, REE, Sr) 3 [CO3] 5
  • Na 3 (Ca, Ce, Sr) 3 (CO 3 ) 5
  • (Na, Ca) 3 (Ca, REE, Sr, Ba) 3 (CO3) 5
  • Na 3 (Ca, Ce, Sr, La) 3 (CO 3 ) 5
Mineral class
(and possibly department) 		Carbonates and nitrates - carbonates without additional anions; without H 2 O
System no. to Strunz
and to Dana 		5.AC.30 ( 8th edition : V / B.07-030 - Lapis classification)
04/14/03/03
Crystallographic Data
Crystal system hexagonal
Crystal class ; symbol dihexagonal-pyramidal; 6 mm
Space group P 6 3 mc (No. 186)Template: room group / 186
Lattice parameters a  = 10.4974  Å ; c  = 6.4309 Å
Formula units Z  = 2
Frequent crystal faces {10 1 0}
Physical Properties
Mohs hardness 3 to 4
Density (g / cm 3 ) 3.43 (measured); 3.46 (calculated)
Cleavage imperfect after {10 1 0}
Break ; Tenacity clamshell; brittle
colour deep orange, pale pink; white, silk white, light beige
Line color White
transparency translucent
shine Glass gloss, silk gloss
radioactivity weakly radioactive
Crystal optics
Refractive indices n ω  = 1.636
n ε  = 1.631
Birefringence δ = 0.005
Optical character uniaxial negative
Pleochroism none
Other properties
Chemical behavior Easily soluble in cold, 10% HCl
Special features no fluorescence

Calcioburbankit is a rarely occurring mineral from the mineral class of " carbonates and nitrates " (formerly carbonates, nitrates and borates ). It crystallizes in the hexagonal crystal system with the idealized chemical composition Na 3 (Ca, Ce, Sr, La) 3 (CO 3 ) 5 - so from a chemical point of view it is a sodium - calcium - carbonate with more or less high contents of strontium , barium and REE . Due to the cerium content , the mineral can be radioactive .

Calcioburbankite often forms isometric to prismatic crystals up to 2 cm in length and fibrous crystal ends with poorly formed, parallel to the c-axis stretched, isometric to prismatic crystals.

The type locality of the Calcioburbankit is the former "Poudrette-Quarry" or the former "Demix Quarry" on Mont Saint-Hilaire ( coordinates of Mont Saint-Hilaire ), Regional County Community of La Vallée-du-Richelieu , Montérégie , Québec , Canada .

Etymology and history

In 1972 the Canadian Museum of Nature (CMN) in Ottawa , Canada , acquired a mineral specimen found in the late 1960s by the mineral collector Jacques Bradley in the “Poudrette Quarry” or in the “Demix Quarry” on Mont Saint-Hilaire. Years later, a program was initiated in which, together with other carbonate minerals from Mont Saint-Hilaire from the museum's collection and from collections by museum staff, the stage acquired in 1972 was examined, which turned out to be a new phase. After determining the necessary crystallographic, physical and chemical-crystal-chemical properties, the mineral was submitted to the International Mineralogical Association (IMA), which recognized it as a new mineral in 1993 under the provisional designation "IMA 1993-001".

In 1995, this mineral was first described scientifically by a team of Canadian scientists with Jerry Van Velthuizen, Robert A. Gault and Joel D. Grice in the Canadian science magazine The Canadian Mineralogist as Calcioburbankit ( English Calcioburbankite , Russian Кальциобурбанкит ). They named the mineral because of its crystal-chemical relationship with burbankite and the dominant chemical element on the B position of the crystal structure.

The type material for calcioburbankite (holotype) is stored under catalog number 50804 in the collection of the Canadian Museum of Nature, Ottawa, Canada.

classification

Since the Calcioburbankit was only recognized as an independent mineral by the IMA in 1993 and the discovery was only published in 1995, it is not listed in the 8th edition of the Strunz mineral classification, which has been out of date since 1977 . There it would have belonged to the common mineral class of "carbonates, nitrates and borates" and there to the department of "carbonates", where together with Burbankit , Bütschliit , Carbocernait , Eitelite , Fairchildite , Nyerereit , Sahamalith and Shortit, it formed the "Eitelite Sahamalith group" “With the system no. Vb / A.05 within the sub-section “Anhydrous carbonates without foreign anions ”.

In the Lapis mineral directory , which was last revised and updated in 2018 , which is still based on the outdated system of Karl Hugo Strunz out of consideration for private collectors and institutional collections , the mineral was given the system and mineral number. V / B.07-030 . In the "Lapis system" this corresponds to the section "Anhydrous carbonates [CO 3 ] 2− , without foreign anions ", where calcioburbankite together with Rémondite (La) , Rémondite (Ce) , Petersenite (Ce) , Burbankite, Khanneshit , Sanrománit and Carbocernait the Burbankit series with the system no. V / B.07 forms.

The 9th edition of Strunz's mineral systematics, which has been valid since 2001 and was updated by the IMA until 2009, assigns the Calcioburbankit to the “carbonates and nitrates” class, which has been reduced by the borates, and to the “carbonates without additional anions” section; without H 2 O “. However, this is further subdivided according to the predominant element group in the compound (alkali and / or alkaline earth metals), so that the mineral can be found according to its composition in the subdivision “ Alkali and alkaline earth carbonates”, where it is found together with burbankite, khanneshit and Sanrománit the "Burbankit group" with the system no. 5.AC.30 forms.

The systematics of minerals according to Dana , which is mainly used in the English-speaking area , assigns the Calcioburbankit, like the outdated Strunz system, to the common class of “carbonates, nitrates and borates” and there to the “anhydrous carbonates” category. Here it is together with Burbankit, Khanneshit and Sanrománit in the " Burbankit group (hexagonal) " with the system no. 04/14/04 within the sub-section "Anhydrous carbonates with a compound formula A 2+ B 2+ 2 (CO 3 ) 4 ".

Chemism

Mean values from three microprobe analyzes on three calcioburbankite grains from an altered pegmatite of the type locality yielded 15.17% Na 2 O; 11.81% CaO; 0.46% BaO; 7.65% SrO; 9.30% La 2 O 3 ; 14.38% Ce 2 O 3 ; 1.26% Pr 2 O 3 ; 3.76% Nd 2 O 3 ; 0.48% Sm 2 O 3 ; 35.13% CO 2 (calculated from stoichiometry); Total 99.40%. Possible contents of Y , Eu , Gd , Tb , Dy , Ho , Er , Tm , Yb , Lu and Th could not be detected. Based on 15 oxygen atoms, the empirical formula Na 3.07 (Ca 1.32 Ce 0.55 Sr 0.46 La 0.36 Nd 0.14 Pr 0.05 Sm 0.02 Ba 0.02 ) Σ = 2.92 (CO 3 ) 5 , which can be idealized to Na 3 (Ca, REE, Sr) 3 (CO3) 5 . An equally from the type locality, but from a marble - Xenolith in contact with hornfels derived Calcioburbankit proved La-rich (with La> Ce) and delivered 13.81% Na 2 O; 12.48% CaO; 6.00% BaO; 7.90% SrO; 12.51% La 2 O 3 ; 10.89% Ce 2 O 3 ; 0.74% Nd 2 O 3 ; 34.98% CO 2 (calculated from stoichiometry); Total 100.64%.

The official formula of the IMA for the Calcioburbankit takes into account the fact of an occasional La supremacy among the SEE and varies the formula of van Velthuisen and colleagues to Na 3 (Ca, Ce, Sr, La) 3 (CO 3 ) 5 The formula notation Strunz is Na 3 (Ca, REE, Sr) 3 [CO3] 5 and is identical to the formula by van Velthuisen and colleagues for the Calcioburbankit - however, here, as usual, the anion group is summarized in square brackets.

The sole combination of elements Na – Ca – Ce – Sr – La – C – O, as can be found in the official IMA formula for calcioburbankite, only has calcioburbankite among the currently known minerals (as of 2020). Chemically similar are burbankite, (Na, Ca) 3 (Sr, Ba, Ce) 3 (CO 3 ) 5 , carbocernaite , (Ca, Na) 3 (Sr, Ce, Ba) 3 (CO 3 ) 5 , khanneshite , ( Na, Ca) 3 (Ba, Sr, Ce, Ca) 3 (CO 3 ) 5 , and the unnamed phase UM1990-98-CO: BaCaNaREESr , (Na, Ca) 3 (Sr, Ba, Ce) 3 (CO 3 ) 5 .

Calcioburbankite can be viewed as the Ca-dominant analogue of the Sr-dominated burbankite, with strontium dominating the cations on the B position in the latter .

From a chemical point of view, like burbankite, khanneshite, rémondite (Ce), rémondite (La) and petersenite (Ce), calcioburbankite belongs to the burbankite group, which is a group of six minerals with the general formula А 3 В 3 (СО 3 ) 5 and А = Na > Ca , SEE 3+ or a vacancy (◻) as well as B = Sr , Ca, Ba , SEE 3+ and / or Na. All representatives of this Burbankit group investigated by Julia Belovitskaya and Igor Pekov (94 analyzes) can be used in an isomorphic system with the - hypothetical - end members (Na 2 Ca) М 2+ 3 (CO 3 ) 5 and Na 3 (SEE 2 Na) (CO 3 ) 5 , with М 2+  = Sr, Ba and / or Ca, can be described.

Crystal structure

The current study on the crystal structure of the Calcioburbankit according to the official IMA list comes from Julia Belovitskaya and colleagues. Calcioburbankite then crystallizes in the hexagonal crystal system in the space group P 6 3 mc (space group no. 186) with the lattice parameters a = 10.4974  Å and c = 6.4309 Å and two formula units per unit cell . Template: room group / 186

As with all representatives of the Burbankit group, eight-coordinate polyhedra with common faces (in this case Na [8] polyhedra) form chains in the direction of the c-axis [0001] in the crystal structure of the calcioburbankite . The chains are linked by ten-coordinate polyhedra (in this case (Ca, SEE, Sr) [10] polyhedra) and CO 3 groups. Two of the five CO 3 groups are in the (0001) plane, the other three are inclined. In detail, one can imagine that - similar to the burbankite - in the crystal structure of the calcioburbankite there are two independent and ordered cation positions in the centers of polyhedra with eight or ten vertices ( A and B ), which are Atoms and three types of carbonate groups labeled C (1), C (2) and C (3) with different orientations are formed. In the Calcioburbankit the polyhedra with ten vertices ( B ) are predominantly occupied by Ca. This is reflected in both unit cell parameters of the Calcioburbankit, the values ​​of which are lower than those of the Burbankit. In addition to Ca, this B position is occupied by Sr, SEE and, to a lesser extent, by Ba and Na. The incorporation of Na atoms into the ten-vertex polyhedra is typical for Rémondit . In the calcioburbankite structure - in contrast to burbankite and khanneshite - the A position is not only occupied by Na and Ca, but also by a small amount of REE. Calcioburbankit was the first representative of minerals of this structure type, in which the presence of SEE on the A position was observed.

Calcioburbankite is isotypic (isostructural) with Burbankite and Khanneshite .

properties

morphology

At the type locality, calcioburbankite is often found in poorly formed, parallel [0001] stretched, prismatic crystals of up to 2 cm in length with the prism determining the costume {10 1 0} or in the form of more or less isometric, according to {10 1 0} prismatic crystals with the basic pinacoid {0001} and fibrous terminations (crystal ends). These crystals are occasionally converted to ankylite (Ce) on the surface. Furthermore, up to 4 mm long, sharp-edged, waxy, prismatic crystals with pyramidal end faces have been described. White to beige-colored epitaxial overgrowths on petersenite (Ce) crystals are said to be the most common . All of these varieties come from hydrothermally converted, SEE-rich pegmatite zones in Mont Saint-Hilaire. A single find in a marble - Xenolith delivered short prismatic, up to 1.5 mm long prismatic crystals having the dipyramid {10 1 1}.

physical and chemical properties

The crystals of the calcioburbankite of the type locality are deep orange, pale pink, white, silky white or light beige. Its stroke color is indicated as white. The surfaces of the translucent crystals of the Calcioburbankit show a characteristic glass-like and occasionally silk-like sheen . Calcioburbankite has a high light refraction ( n ε  = 1.631; n ω  = 1.636), but only a very low birefringence (δ = 0.005) , corresponding to this glass gloss . In transmitted light, the uniaxial negative calcioburbankite is colorless and shows no pleochroism .

Calcioburbankite has an imperfect cleavage according to {10 1 0}. Due to its brittleness , however , the mineral breaks in a similar way to quartz , with the fracture surfaces being shell-shaped. Calcioburbankit has a Mohs hardness of 3 to 4 and is therefore one of the medium-hard minerals that, like the reference minerals calcite (hardness 3), can be easily scratched with a copper coin and fluorite (hardness 4) with a pocket knife. The measured density for calcioburbankite is 3.43 g / cm³, the calculated density is 3.46 g / cm³.

The mineral is neither (356 nm) (nm 254) in the long wavelength even in the short wavelength light UV a fluorescence . Calcioburbankit is easily soluble in cold 10% hydrochloric acid , HCl.

Precautions

Calcioburbankit is classified as weakly radioactive due to its content of rare earth elements and radioactive isotopes of the REE cerium and lanthanum and has a specific activity of about 488  Bq / g (for comparison: natural potassium 30.346 Bq / g). In spite of the only weak radioactivity of the mineral, mineral samples from Calcioburbankit should only be kept in dust and radiation-proof containers, but above all never in living rooms, bedrooms or work rooms. Absorption into the body (incorporation, ingestion ) should also be prevented in any case and, for safety, direct body contact should be avoided and respiratory protection mask and gloves should be worn when handling the mineral .

Education and Locations

Calcioburbankite is a late-formed mineral and was found in SEE-rich, hydrothermally transformed zones of pegmatites and in a marble xenolite in the vicinity of a nepheline syenite complex. In addition, occurrences of calcioburbankite in carbonatites ("Vuorijärvi"; Chibinen ; "Arbarastakh", Yakutia; "Srednjaja Zima", Siberia) have been identified.

Accompanying minerals of the calcioburbankite at its type locality are ankylite (Ce) , calcite , donnayite (Y) , fluoroapatite , natrolite , pyrite , rhodochrosite , rutile and a mineral of the chlorite group in the converted pegmatites ; in marble xenolite, however, aegirine , calcite, fluorite , galena , leucophanite , manganese neptunite , microcline , molybdenite-2H and molybdenite-3R , narsarsukite , pectolite , pyrite, shairerite , shortite , sodalite , sphalerite , thermonatrite and titanite . In epitaxies it coats petersenite (Ce).

As a very rare mineral formation, calcioburbankite (as of 2020) is only known from around five other sites in addition to its type locality. The type locality of the Calcioburbankit is the former "Poudrette-Quarry" or the former "Demix Quarry" on Mont Saint-Hilaire , Regional County Community of La Vallée-du-Richelieu , Montérégie , Québec , Canada .

Other localities for calcioburbankite are:

Locations for Calcioburbankit from Germany , Austria and Switzerland are therefore unknown.

use

Due to its rarity, calcioburbankite has no commercial significance and is only of interest to mineral collectors.

See also

literature

  • Jerry Van Velthuizen, Robert A. Gault, Joel D. Grice: Calcioburbankite, Na 3 (Ca, REE, Sr) 3 (CO 3 ) 5 , a new mineral species from Mont Saint-Hilaire, Quebec, and its relationship to the burbankite group of minerals . In: The Canadian Mineralogist . tape 33 , no. 6 , 1995, pp. 1231–1235 (English, rruff.info [PDF; 485 kB ; accessed on February 29, 2020]).
  • Calcioburbankite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 67 kB ; accessed on February 29, 2020]).

Web links

Individual evidence

  1. ↑ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af ag ah ai aj ak al am Jerry Van Velthuizen, Robert A. Gault, Joel D. Grice: Calcioburbankite, Na 3 (Ca, REE, Sr) 3 (CO 3 ) 5 , a new mineral species from Mont Saint-Hilaire, Quebec, and its relationship to the burbankite group of minerals . In: The Canadian Mineralogist . tape 33 , no. 6 , 1995, pp. 1231–1235 (English, rruff.info [PDF; 485 kB ; accessed on February 29, 2020]).
  2. ↑ a b c d 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.  291 (English).
  3. ↑ a b c d Calcioburbankite . In: John W. Anthony, Richard A. Bideaux, Kenneth W. Bladh, Monte C. Nichols (Eds.): Handbook of Mineralogy, Mineralogical Society of America . 2001 ( handbookofmineralogy.org [PDF; 67  kB ; accessed on February 29, 2020]).
  4. ↑ a b c d e f g Yulia V. Belovitskaya, Igor V. Pekov, Elena R. Gobechiya, Y. K Kabalov, Victor V. Subbotin: Crystal structure of calcioburbankite and the characteristic features of the burbankite structure type . In: Crystallography Reports . tape 46 , no. 6 , 2004, p. 927-931 ( rruff.info [PDF; 67 kB ; accessed on February 29, 2020]).
  5. ↑ a b c Malcolm Back, William D. Birch, Michel Blondieau and others: The New IMA List of Minerals - A Work in Progress - Updated: January 2020. (PDF; 1762 kB) In: cnmnc.main.jp. IMA / CNMNC, Marco Pasero, January 2020, accessed January 20, 2020 .
  6. ↑ a b c d László Horváth, Elsa Pfenninger-Horváth: The minerals of Mont-Saint-Hilaire . In: Lapis . tape 25 , no. 7/8 , 2000, pp. 28 .
  7. ^ A b David Barthelmy: Calcioburbankite Mineral Data. In: webmineral.com. Retrieved February 29, 2020 .
  8. ↑ Stefan Weiß: The large Lapis mineral directory. All minerals from A - Z and their properties. Status 03/2018 . 7th, completely revised and supplemented edition. Weise, Munich 2018, ISBN 978-3-921656-83-9 .
  9. ↑ Ernest H. Nickel, Monte C. Nichols: IMA / CNMNC List of Minerals 2009. (PDF; 1703 kB) In: cnmnc.main.jp. IMA / CNMNC, January 2009, accessed September 25, 2019 .
  10. ^ Minerals with Na-Ca-Ce-Sr-La-C-O. In: mindat.org. Hudson Institute of Mineralogy, accessed February 29, 2020 .
  11. ↑ a b c d Yulia V. Belovitskaya, Igor V. Pekov: Genetic mineralogy of the burbankite group . In: Genetic mineralogy of the burbankite group . tape 39 , 2004, p. 50-64 ( rruff.info [PDF; 1.1 MB ; accessed on October 4, 2019]).
  12. ↑ a b c László Horváth: Mineral Species discovered in Canada and species named after Canadians (The Canadian Mineralogist Special Publication 6) . 1st edition. Mineralogical Association of Canada, Ottawa 2003, ISBN 0-921294-40-9 , pp. 31 .
  13. ↑ Localities for Calcioburbankite. In: mindat.org. Hudson Institute of Mineralogy, accessed February 29, 2020 .
  14. ↑ a b c List of localities for Calcioburbankit from the Mineralienatlas and Mindat (accessed on February 29, 2020)
  15. ↑ a b Calcioburbankite. In: mindat.org. Hudson Institute of Mineralogy, accessed February 29, 2020 .
  16. ↑ LK Pozharitskaya, VS Samoilov: Petrologiya, mineralogiya, i geokhimiya karbonatitov Vostochnoi Sibiri (Petrology, Mineralogy and Geochemistry of Carbonatites from East Siberia) . 1st edition. Nauka, Moscow 1972, p. 1–268 (Russian).