Hellandite-(Y) (original) (raw)

A valid IMA mineral species

About Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Formula:

(Ca,REE)4Y2Al◻2(B4Si4O22) (OH)2

In the IMA approved report on hellandites [Am. Mineral.,87 (2002), 745–752], the occupancy at the T sites was given as (Be,Li)2–x, however the value of x was not specified. Actually, it is always x > 1, therefore the T site is vacant in the ideal formula of hellandite-(Y).

Colour:

Nut-brown, brownish red, black, gray, green, yellow, cream, pinkish

Specific Gravity:

2.95 - 3.63

Crystal System:

Monoclinic

Name:

Named in 1903 by Waldemar Christofer Brøgger in honour of Amund Theodor Helland (11 October 1846, Bergen, Norway - 15 November 1918, Kristiania (now Oslo), Norway), professor of geology and geography at the Royal Frederick University (University of Oslo). It was renamed in 1987, but the renaming was not approved until 2002 (IMA Case 00-F). The suffix/modifier indicates the dominant essential REE.

Unique IdentifiersHide

This section is currently hidden. Click the show button to view.

Long-form identifier:

mindat:1:1:1852:0

4594b406-caeb-4ef4-b239-21e424c76b5a

IMA Classification of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

IMA status notes:

Redefined by the IMA

IMA Formula:

(Ca,REE)4Y2Al◻2(B4Si4O22)(OH)2

Approval history:

Redefined as hellandite-(Y) by IMA in 2000 (special procedure IMA code 00-F).
Revision of formula: IMA 2017 (CNMNC Newsletter No. 37).

Classification of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

9.DK.20

9 : SILICATES (Germanates)
D : Inosilicates
K : Inosilicates with 5-periodic single chains

54.2.2.1

54 : NESOSILICATES Borosilicates and Some Beryllosilicates
2 : Borosilicates and Some Beryllosilicates with B in [4] coordination

17.5.51

17 : Silicates Containing other Anions
5 : Borosilicates

Mineral SymbolsHide

This section is currently hidden. Click the show button to view.

As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.

Physical Properties of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Colour:

Nut-brown, brownish red, black, gray, green, yellow, cream, pinkish

Cleavage:

Poor/Indistinct
Poor on {100}, {010}.

Density:

2.95 - 3.63 g/cm3 (Measured) 3.5(5) g/cm3 (Calculated)

Optical Data of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

RI values:

_n_α = 1.640 _n_β = 1.650 _n_γ = 1.660

2V:

Measured: 48° to 86°, Calculated: 88°

δ = 0.020

Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.

Dispersion:

relatively weak

Chemistry of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Mindat Formula:

(Ca,REE)4Y2Al◻2(B4Si4O22) (OH)2

In the IMA approved report on hellandites [Am. Mineral.,87 (2002), 745–752], the occupancy at the T sites was given as (Be,Li)2–x, however the value of x was not specified. Actually, it is always x > 1, therefore the T site is vacant in the ideal formula of hellandite-(Y).

Crystallography of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Crystal System:

Monoclinic

Class (H-M):

2/m - Prismatic

Cell Parameters:

a = 18.99(1) Å, b = 7.715(5) Å, c = 10.30(1) Å
β = 111.4(1)°

Ratio:

a:b:c = 2.461 : 1 : 1.335

Unit Cell V:

1,404.99 ų (Calculated from Unit Cell)

Twinning:

Contact and polysynthetic, parallel to {001} and {100}.

Crystal StructureHide

This section is currently hidden. Click the show button to view.

Load
Unit Cell |Unit Cell Packed
2x2x2 |3x3x3 |4x4x4

Show
Big Balls |Small Balls |Just Balls |Spacefill
Polyhedra Off |Si Polyhedra |All Polyhedra
Remove metal-metal sticks

Display Options
Black Background |White Background
Perspective On |Perspective Off
2D |Stereo |Red-Blue |Red-Cyan

View
CIF File Best |x |y |z |a |b |c

Rotation
Stop |Start

Labels
Console Off |On |Grey |Yellow

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0000557	Hellandite-(Y)	Mellini M, Merlino S (1977) Hellandite: a new type of silicoborate chain American Mineralogist 62 89-99		1977	0	293
0020232	Hellandite-(Y)	Miyawaki R, Momma K, Yokoyama K, Shigeoka M, Matsubara S, Ito M, Nakai I, Kristiansen R (2015) Mn-bearing hellandite-(Y) from the Heftetjern pegmatite, Tordal, Norway The Canadian Mineralogist 53 345-356	2015	Heftetjern, Tordal, Telemark, Norway	0	293

CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

This section is currently hidden. Click the show button to view.

Powder Diffraction Data:

Geological EnvironmentHide

This section is currently hidden. Click the show button to view.

Type Occurrence of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Place of Conservation of Type Material:

Mineralogical-Geological Museum, University of Oslo, Oslo, Norway, numbers 21846, various (cotype).
Muséum Nationale d’Histoire Naturelle, Paris, France, number 109732 (type).

Associated Minerals at Type Locality:

Synonyms of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Other Language Names for Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Varieties of Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Relationship of Hellandite-(Y) to other SpeciesHide

This section is currently hidden. Click the show button to view.

Other Members of this group:

Structurally related to group(s):

Common AssociatesHide

This section is currently hidden. Click the show button to view.

Associated Minerals Based on Photo Data:

Related Minerals - Strunz-mindat GroupingHide

This section is currently hidden. Click the show button to view.

Other InformationHide

This section is currently hidden. Click the show button to view.

Health Risks:

No information on health risks for this material has been entered into the database. You should always treat mineral specimens with care.

Internet Links for Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

References for Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

Reference List:

Oberti, Roberta, Ventura, Giancarlo Della, Ottolini, Luisa, Hawthorne, Frank C., Bonazzi, Paola (2002) Re-definition, nomenclature and crystal-chemistry of the hellandite group. American Mineralogist, 87 (5) 745-752 doi:10.2138/am-2002-5-618

Miyawaki, Ritsuro, Momma, Koichi, Yokoyama, Kazumi, Shigeoka, Masako, Matsubara, Satoshi, Ito, Miku, Nakai, Izumi, Kristiansen, Roy (2015) Mn-bearing hellandite-(Y) from Heftetjern pegmatite, Tørdal, Norway. The Canadian Mineralogist, 53 (2) 345-356 doi:10.3749/canmin.1400068

Ondrejka, Martin, Molnárová, Alexandra, Putiš, Marián, Bačík, Peter, Uher, Pavel, Voleková, Bronislava, Milovská, Stanislava, Mikuš, Tomáš, Pukančík, Libor (2022) Hellandite-(Y)–hingganite-(Y)–fluorapatite retrograde coronae: a novel type of fluid-induced dissolution–reprecipitation breakdown of xenotime-(Y) in the metagranites of Fabova Hoľa, Western Carpathians, Slovakia. Mineralogical Magazine, 86 (4) 586-605 doi:10.1180/mgm.2022.7

Localities for Hellandite-(Y)Hide

This section is currently hidden. Click the show button to view.

This map shows a selection of localities that have latitude and longitude coordinates recorded. Click on the symbol to view information about a locality. The symbol next to localities in the list can be used to jump to that position on the map.

Locality ListHide

This section is currently hidden. Click the show button to view.

- This locality has map coordinates listed. - This locality has estimated coordinates. ⓘ - Click for references and further information on this occurrence. ? - Indicates mineral may be doubtful at this locality. - Good crystals or important locality for species. - World class for species or very significant. (TL) - Type Locality for a valid mineral species. (FRL) - First Recorded Locality for everything else (eg varieties). Struck out - Mineral was erroneously reported from this locality. Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).

All localities listed without proper references should be considered as questionable.