Niveolanite
| Niveolanite | |
|---|---|
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| General and classification | |
| other names |
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| chemical formula |
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Mineral class (and possibly department) |
Carbonates and nitrates |
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System no. to Strunz and to Dana |
5.DC.35 ( 8th edition : V / E.08-001) 16b.03.04.01 |
| Crystallographic Data | |
| Crystal system | tetragonal |
| Crystal class ; symbol | ditetragonal-dipyramidal; 4 / m 2 / m 2 / m |
| Space group | P 4 / mcc (No. 124) |
| Lattice parameters | a = 13.1304 Å ; c = 5.4189 Å |
| Formula units | Z = 8 |
| Frequent crystal faces | {100}, {110} |
| Twinning | spread |
| Physical Properties | |
| Mohs hardness | not specified |
| Density (g / cm 3 ) | 2.06 (calculated from the empirical formula); 1.82 (calculated from the structural data) |
| Cleavage | none (also no divisibility) |
| Break ; Tenacity | splintery; brittle (crystals) or inelastic flexible (aggregates) |
| colour | colorless (crystals); snow white to pearly white (aggregates); colorless in transmitted light |
| Line color | White |
| transparency | transparent (crystals) |
| shine | Silky gloss |
| Crystal optics | |
| Refractive indices |
n ω = 1.469 n ε = 1.502 |
| Birefringence | δ = 0.033 |
| Optical character | uniaxial positive |
| Pleochroism | unavailable |
| Other properties | |
| Chemical behavior | Slowly dissolve in dilute and concentrated HCl at room temperature with gentle effervescence |
| Special features | Toxic, as toxic Be 2+ ions are released when dissolved in HCl |
Niveolanit is a very rare mineral from the mineral class of " carbonates and nitrates ". It crystallizes in the tetragonal crystal system with the idealized chemical composition hub (CO 3 ) (OH) · 1-2H 2 O and is therefore chemically seen a hydrous sodium - Beryllium - carbonate with additional hydroxide ions.
Niveolanit mainly forms soft, fibrous aggregates up to 2 cm in size, which are irregular, matted, radial, subparallel, bundle or sheaf-shaped and consist of curved and divergent fibers up to 1.4 cm long and 0.01 mm thick . According to [001], elongated, needle-like crystals up to 1 cm in length and 0.03 mm in thickness, which typically have tetragonal or octagonal cross-sections, are found less frequently.
The Niveolanite type locality is the vein- shaped “Poudrette pegmatite” exposed by the “Poudrette Quarry” ( coordinates of the Poudrette Quarry ) in Mont Saint-Hilaire , Regional County Community of La Vallée-du-Richelieu , Montérégie , Québec , Canada .
Etymology and history
Niveolanite was first found in June 1998 by László Horváth and Elsa Pfenninger-Horváth in the "Poudrette Quarry" and initially considered to be a visually almost identical, only partially investigated, REE-containing carbonate, which was found earlier in another area of the same pegmatite and as "MSH UK-91" was designated. After the mineral was found not to contain REE , it was transferred to the Canadian Museum of Nature (CMN) in Ottawa , Canada for identification in 1999 . After the first X-ray diffractometric and electron- beam microanalytical investigations, it quickly became clear that it was a new phase - a water-containing Na-Ca carbonate - which Robert A. Gault temporarily designated as "MSH UK-113". The attempt to analyze the structure failed, however, because the thin fibers of the new phase could not be used as single crystals. All further investigations of this phase in the CMN were discontinued in 2000.
During an excursion with László Horváth in August 1998, also in the “Poudrette Quarry”, the same mineral was recovered independently by Igor V. Pekov and Dmitriy I. Belakovskiy . X-ray diffraction, electron beam microanalytical and infrared spectroscopic analyzes in Moscow gave the same result as before at the CMN with a water-containing Na-Ca carbonate. Since "MSH UK-113" was not further researched at the CMN, the investigations were transferred in 2006 to the Moscow team led by Igor V. Pekov. Nikita V. Chukanov found that parts of the IR spectrum of this carbonate mineral can only be explained by the presence of a large cation and probably even a high field strength element - which had to be a light element which cannot be detected in routine operation with the microprobe . Analyzes with ICP-OES then did not show the expected lithium , but high beryllium content. In addition, further "MSH UK-113" material with varying accompanying minerals , different morphologies and different collection dates were examined. After completing the investigations and determining all relevant data, the mineral was submitted to the International Mineralogical Association (IMA), which recognized it as a new mineral in 2007 under the provisional designation "IMA 2007-032".
In 2008 the first scientific description of this mineral was made by a team of Russian scientists with Igor V. Pekov, Natalia V. Zubkova , Nikita V. Chukanov, Atali A. Agakhanov , Dmitriy I. Belakovskiy, Yaroslav E. Filinchuk , Elena R. Gobechiya , Dmitriy Yu. Pushcharovsky and Murtazali Kh. Rabadanov and the Canadian hobby mineralogist László Horváth in the Canadian science magazine The Canadian Mineralogist as Niveolanit ( Russian Нивеоланит , English Niveolanite ). They named the mineral after the Latin words niveus and lanas for "snow white" and "wool" - to indicate the visual similarity of typical niveolanite aggregates with flakes of snow-white, fluffy wool.
The type material for Niveolanite (cotypes) is in the systematic collection of the Mineralogical Museum " Alexander Evgenjewitsch Fersman " of the Russian Academy of Sciences in Moscow , Russia , (catalog number 3631/1) and in the collection of the Canadian Museum of Nature, Ottawa, Canada, kept.
classification
Since the Niveolanite was only recognized as an independent mineral in 2007 and was first described in 2008, it is not listed in the 8th edition of the mineral classification according to Strunz, which has been outdated since 1982 . In the "Lapis mineral directory", which was last updated in 2018 and which, out of consideration for private collectors and institutional collections, is still based on this classic system of Karl Hugo Strunz , the mineral was given the mineral and system no. V / E.08-001 , which in the "Lapis system" corresponds to the mineral class of "carbonates, nitrates and borates" and there the section "Hydrogen carbonates with foreign anions". There is Niveolanit together with Thomasclarkit- (Y) , Kamphaugit- (Y) , Calcioankylit- (Ce) , Calcioankylit- (Nd) , Ankylit- (La) , Ankylit- (Ce) , Gysinit- (Nd) , Kochsándorite , Strontiodresserite , Dresserite , hydrodresserite , montroyalite , dundasite , petterdit and barstowite combined in an unnamed group.
The 9th edition of Strunz's mineral systematics, which has been in effect since 2001 and is used by the International Mineralogical Association (IMA), assigns niveolanite to the class of "carbonates and nitrates" (the borates form a separate class here) and there into the department of " Hydrous carbonates with foreign anions ”(carbonates with additional anions; with H 2 O). However, this section is further subdivided according to the size of the cations involved , so that the mineral can be found according to its composition in the sub-section "with large cations", where it is the only member of the unnamed group with the system no. 5.DC.35 forms.
The systematics of minerals according to Dana , which is mainly used in the English-speaking world , assigns niveolanite, like the outdated Strunz system, to the common class of “carbonates, nitrates and borates” and there to the “carbonates - hydroxyl or halogen” class. Here he is the only member of the unnamed group 16b.03.04 within the subdivision “ Carbonates - Hydroxyl or Halogen with A m B n (XO 3 ) p Z q • x (H 2 O), (m + n): p = 2: 1 ”.
Chemism
Mean values from eight microprobe analyzes on Niveolanit from the type locality yielded 19.81% Na 2 O; 0.07% K 2 O; 3.88% CaO; 16.65% BeO (determined via ICP-OES), 29.81% CO 2 (determined via the ignition loss ) and 26.93 H 2 O (determined via the ignition loss) (total 97.15%). The contents of F , Li and B are below the detection limit . The OH: H 2 O ratio was calculated from the charge balance, and the presence of OH, H 2 O and CO 3 was confirmed by IR spectroscopy. The low value for the analytical sum (97.15% by weight) is possibly caused by the zeolitic character of the mineral. Parts of the H 2 O are only weakly bound in the broad channels of the structure and can easily be mobilized during the analysis. Consequently, the H 2 O content can vary from crystal to crystal; The water contents determined using different methods can also differ. From the analyzes, based on one carbon atom per formula unit (pfu), the empirical formula (Na 0.94 Ca 0.10 ) Σ = 1.04 Be 0.98 (CO 3 ) 1.00 (OH) 1.10 · 1.66H 2 O calculated, which can be idealized to NaBe (CO 3 ) (OH) · 1–2H 2 O. The official IMA formula for Niveolanite is NaBe (CO 3 ) (OH) 2H 2 O.
The element combination Na – Be – C – O – H is unique among the currently known minerals; this means that there are no minerals with a chemical composition with the same chemical elements as niveolanite. When it was first described, niveolanite was the hundredth mineral recognized by the IMA with beryllium as an essential, formula-effective component. It is also the first naturally occurring beryllium carbonate. Niveolanite can be described as a Na-Be-dominant analogue to the Hg-dominated minerals peterbaylissite , (Hg + 2 ) 1.5 (CO 3 ) (OH) · 2H 2 O, and Clearcreekit , (Hg + 2 ) 1.5 (CO 3 ) (OH) · 2H 2 O, both of which have a completely different structure.
Crystal structure
Niveolanite crystallizes in the tetragonal crystal system in the space group P 4 / mcc (space group no. 124) with the lattice parameters a = 13.1304 Å and c = 5.4189 Å as well as eight formula units per unit cell . The structural formula for the mineral becomes {(Na 0.9 Ca 0.1 ) [(H 2 O) 0.9 (OH) 0.1 ]} {Be (OH)} (CO 3 ) · 0-1H 2 O specified.
Niveolanit represents a new type of structure. Its crystal structure isolated includes, infinite [- (OH) - (BeO 2 ) -] chains of BeO 2 (OH) 2 - tetrahedra , where adjacent loading tetrahedron with each other via common OH groups are joined. Two more vertices of each Be tetrahedron are shared with (CO 3 ) groups. Na cations sit in the middle of seven-coordinate [NaO 6 (H 2 O)] polyhedra , which are linked to one another via common edges and thus form isolated columns. Each CO 3 group shares two vertices with two neighboring Be tetrahedra, whereas its third vertex is shared with three Na polyhedra, since each CO 3 group is linked by two edges with two Na polyhedra. The chains of Be tetrahedra and columns of Na polyhedra are arranged in the direction of the c-axis [001] and form wide channels in which the H 2 O molecules, which form a vertex of the Na polyhedra, sit. For this reason, Niveolanit can show a zeolite-like behavior.
| Crystal structure of Niveolanit |
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| Color legend: __ Na __ Ca __ Be __ C __ O __ H |
The crystal structure of niveolanite is unique, but there are some structurally similar minerals. In the niveolanite, the bonds between the Be tetrahedra in the direction of [001] are strengthened by CO 3 groups located on both sides of the [BeO 2 (OH)] chains. Consequently the c-period of the structure corresponds almost exactly to two edge lengths of the Be tetrahedron. This structural feature has similarities with the chains in many structures of beryllium minerals, in which the core of the chain is formed by Be tetrahedra. In such minerals, however, the bonds between the neighboring Be tetrahedra are formed by Si tetrahedra (e.g. in Euclas , AlBe (SiO 4 ) (OH), and Sphaerobertrandit , Be 3 SiO 4 (OH) 2 ) or P tetrahedra as in Väyrynenit , MnBe (PO4) (OH), reinforced. Similar elements are found in hopeite , Zn 3 (PO 4 ) 2 (H2O) 4 , and phosphophyllite , Zn 2 Fe (PO 4 ) 2 (H 2 O) 4 , where Zn tetrahedra form the chains and P tetrahedra their contacts amplify. In clinohedrite , CaZn (SiO 4 ) (H 2 O), the (Zn, O) chains are also fixed by Si tetrahedra. Some borate minerals also have structural similarities to niveolanite. Calciborite , Ca 2 (BO 3 BO) 2 , with chains of B tetrahedra and planar B triangles has the same configuration as the Be-C chains in niveolanite. Dundasit , PBAL 2 (CO 3 ) 2 (OH) 4 · H 2 O, and related minerals with it have a configuration with chains from Al - octahedra with common edges, wherein two additional vertices as CO 3 are connected as groups in the structure of niveolanite.
properties
morphology
Niveolanite is found in the cavities of a pegmatite and there typically in the spaces between microcline and aegirine crystals. It forms two morphologically different varieties: fibrous aggregates and needle-like crystals. The fibrous aggregates are irregular, matted, radial, subparallel, bundle or sheaf-shaped, reach up to 2 cm in size and are usually soft, inelastic, pliable and fluffy like flakes of wool. Individual fibers are typically curved and divergent and reach dimensions of up to 1.4 cm in length and up to 0.01 mm in thickness.
In some cavities, needle-like crystals up to 1 cm in length and 0.03 mm in thickness, elongated according to [001], typically have tetragonal (square) or octagonal cross-sections. These crystals show the shape of the tetragonal prism II position {100} and the tetragonal prism I position {110}; however, there are no well-formed end faces. Some of the crystals are actually parallel adhesions of extremely thin, needle-like sub-individuals. Finally, fibrous pseudomorphoses of niveolanite after lamellar eudidymite crystals up to 0.1 × 0.5 × 1 cm in size were observed; the beryllium content of the newly formed niveolanite is derived directly from the eudidymite.
physical and chemical properties
Niveolanit aggregates are snow-white to pearly white, while the crystals are colorless, water-clear. Their line color , however, is always white. The surfaces of the transparent crystals as well as those of the aggregates show a characteristic silky sheen . Aggregates are translucent to opaque. Corresponding to this silk gloss, Niveolanit has a mean light refraction ( n ω = 1.469; n ε = 1.502) and a mean birefringence (δ = 0.033). In transmitted light, the uniaxial positive niveolanite is colorless and has no pleochroism .
Niveolanit shows neither cleavage nor divisibility. Due to its brittleness , however, niveolanite crystals break in a similar way to willemite or Vesuvian , whereby the break surfaces are splintered. Fibrous aggregates, however, are inelastic and flexible. The Mohs hardness of the mineral cannot be determined due to the wool-like aggregates and the extremely thin needles. The calculated density of the Niveolanite is 2.06 g / cm³ (calculated from the empirical formula) or 1.82 g / cm³ (calculated from the structural data).
Niveolanit crystals show neither in the short wavelength even in the long wavelength UV light , a fluorescent . The crystals of Niveolanite dissolve slowly at room temperature in both dilute and concentrated hydrochloric acid , HCl, with a very gentle bubbling. In humid air, Niveolanit shows strong absorption of molecular water; its hydration - dehydration process therefore depends on the air humidity and is reversible.
toxicity
As a mineral containing beryllium, niveolanite is potentially toxic , which is why skin contact with the mineral and the absorption of niveolanite fibers contained in the breath should be avoided. Due to the instability of the mineral in the presence of acids , toxic Be 2+ ions are released, which is why niveolanite must be regarded as a toxic mineral.
Education and Locations
Niveolanit was found at its type locality in the so-called "Poudrette pegmatite" of the largest discovered in the complex of Mont Saint-Hilaire Pegmatitkörper forms. It represents a late-formed mineral and is found in cavities of a hydrothermally modified peralkaline pegmatite. Typically it also occurs in pseudomorphoses after another beryllium mineral. The Poudrette pegmatite is highly enriched with various other carbonate minerals formed in the late stages of pegmatite development. Besides Niveolanit there are also significant amounts of zirconium - titanium carbonate Sabinait . This exotic carbonate mineralization points to the extremely high CO 2 activity of the late hydrothermal solutions, which not only dissolved the rare metal silicates formed earlier, but also enabled the crystallization of carbonates containing these remobilized cations.
Typical accompanying minerals of the niveolanite in the cavities in the "poudrette pegmatite" are albite (mostly in epitaxial adhesions on microcline ), aegirine , natrolite , gonnardite (always epitaxially on natrolite), siderite , parsenite (Ce) , franconite and fine, powdery Dawsonite . Less frequently socialized minerals are analcime , quartz , Eudidymit , Katapleiit , Gaidonnayit , monazite (Ce) , calcite , Adamsit- (Y) , Shomiokit- (Y) , galena , sphalerite and rutile and Shortite , Hochelagait and rhodochrosite . Brown films of a solid bituminous substance were observed in some cavities with Niveolanit . In these areas, microcline, aegirine, nepheline, albite, annite , sodalite and zircon form the massive pegmatite matrix.
As an extremely rare mineral formation, the Niveolanite has so far (as of 2019) only been described by one point of discovery. The type locality for Niveolanit is the “Poudrette pegmatite” exposed in the “Poudrette Quarry” in the alkaline rock pluton of Mont Saint-Hilaire , Regional County Community of La Vallée-du-Richelieu , Montérégie , Québec , Canada . The “Poudrette Quarry” also includes the quarries in the former “Demix Quarry”, which were sold to the Poudrette family in 1994 and into which the old “Desourdy Quarry” and “Uni-Mix Quarry” quarries had merged earlier. At the end of 2007, the Poudrette family sold the quarry, the name of which has since been given as “Carrière Mont Saint-Hilaire”. The vein-shaped Poudrette pegmatite is located at the southernmost corner of the new “Poudrette Quarry”, which unites the former “Demix Quarry” in the northwest with the original “Poudrette Quarry” in the southeast to form a single quarry. It is 2–4 m thick, at least 70 m long and was vertically exposed to about 35–40 m. The first Niveolanit steps were made on sole no. 8 recovered from the quarry. Possibly the richest zone was on the temporarily exposed No. 9, in trench excavations, in the main pegmatite tunnel and some "offshoot" tunnels that were found in 2000 and 2002. It is very likely that there are still other Niveolanite deposits in the as yet undeveloped parts of the quarry.
Sites for Niveolanite from Germany , Austria and Switzerland are therefore unknown.
use
Due to its rarity, niveolanite is only of interest to the collector of minerals.
See also
literature
- Igor V. Pekov, Natalia V. Zubkova, Nikita V. Chukanov, Atali A. Agakhanov, Dmitriy I. Belakovskiy, László Horváth, Yaroslav E. Filinchuk, Elena R. Gobechiya, Dmitriy Yu. Pushcharovsky, Murtazali Kh. Rabadanov: Niveolanite, the first natural beryllium carbonate, a new mineral species from Mont Saint-Hilaire, Quebec, Canada . In: The Canadian Mineralogist . tape 46 , no. 5 , 2008, p. 1343–1354 , doi : 10.3749 / canmin.46.5.1343 (English, rruff.info [PDF; 1.1 MB ; accessed on March 11, 2019]).
- Niveolanite . 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; 51 kB ; accessed on March 11, 2019]).
Web links
- Mineral Atlas: Niveolanit (Wiki)
- Niveolanite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 11, 2019 .
- David Barthelmy: Niveolanite Mineral Data. In: webmineral.com. Retrieved March 11, 2019 .
- American-Mineralogist-Crystal-Structure-Database - Niveolanite. In: rruff.geo.arizona.edu. Retrieved March 11, 2019 .
Individual evidence
- ↑ 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 an ao ap aq ar as at au av aw ax ay Igor V. Pekov, Natalia V. Zubkova, Nikita V. Chukanov, Atali A. Agakhanov, Dmitriy I. Belakovskiy, László Horváth, Yaroslav E. Filinchuk, Elena R. Gobechiya, Dmitriy Yu. Pushcharovsky, Murtazali Kh. Rabadanov: Niveolanite, the first natural beryllium carbonate, a new mineral species from Mont Saint-Hilaire, Quebec, Canada . In: The Canadian Mineralogist . tape 46 , no. 5 , 2008, p. 1343–1354 , doi : 10.3749 / canmin.46.5.1343 (English, rruff.info [PDF; 1.1 MB ; accessed on March 11, 2019]).
- ↑ Niveolanite . 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; 51 kB ; accessed on March 11, 2019]).
- ↑ a b IMA / CNMNC List of Mineral Names; November 2018 (PDF 1.65 MB)
- ↑ a b c d e Niveolanite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 11, 2019 .
- ↑ a b 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 .
- ↑ Localities for Niveolanite. In: mindat.org. Hudson Institute of Mineralogy, accessed March 11, 2019 .
- ↑ Find location list for Niveolanite at the Mineralienatlas and at Mindat (accessed on March 11, 2019)
- ↑ Description of Poudrette Quarry. In: mindat.org. Hudson Institute of Mineralogy, accessed March 11, 2019 .