Cuatrocapaite-(NH4)
A valid IMA mineral species
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About Cuatrocapaite-(NH4)
Formula:
(NH4)3(NaMg◻)(As2O3)6Cl6 · 16H2O
Colour:
colorless to white
Lustre:
Vitreous
Hardness:
2½
Specific Gravity:
2.65
Crystal System:
Trigonal
Member of:
Name:
The name cuatrocapaite-(NH4) is in allusion to the structure, which consists of four (cuatro in Spanish) different types of layers (capa in Spanish): (1) [(NH4),K],(2)[(Na,Mg,□)3(H2O)16],(3) [As2O3] and (4) [Cl6]. The -(NH4) suffix indicates the dominant cation in the large-cation layer. The IPA pronunciation of cuatrocapaite is (/kwa: troʊ'ka:pa: aɪt/).
The NH4 analogue of cuatrocapaite-(K) (IMA No. 2018-084). Unique combination of elements (status: September 2022).
There are 4 types of layers in the structure:
- a planar, neutral As2O3 (arsenite) one,
- an (NH4+,K+) layer standing for a link for the adjacent arsenite sheets,
- a Cl– one, located on the As sides of the arsenite layers,
- a layer with partially occupied Na, Mg, and H2O sites, flanked on both its sides by the Cl- layers.
The layer sequence of the first three types of layers is identical that observed in lucabindiite and gajardoite.
There are 4 types of layers in the structure:
- a planar, neutral As2O3 (arsenite) one,
- an (NH4+,K+) layer standing for a link for the adjacent arsenite sheets,
- a Cl– one, located on the As sides of the arsenite layers,
- a layer with partially occupied Na, Mg, and H2O sites, flanked on both its sides by the Cl- layers.
The layer sequence of the first three types of layers is identical that observed in lucabindiite and gajardoite.
Name Encoding
Formatted:
cuatrocapaite-(NH4)
HTML:
cuatrocapaite-(NH<sub>4</sub>)
LaTeX:
cuatrocapaite-(NH\$\_4\$)
Unique Identifiers
Mindat ID:
53209
Long-form identifier:
mindat:1:1:53209:1
Similar Names
| Cuatrocapaite-(K) | A valid IMA mineral species | K3(NaMg◻)(As2O3)6Cl6 · 16H2O |
IMA Classification of Cuatrocapaite-(NH4)
Approved
Approval year:
2018
First published:
2019
Type description reference:
Kampf, Anthony R., Chukanov, Nikita V., Möhn, Gerhard, Dini, Maurizio, Molina Donoso, Arturo A., Friis, Henrik (2019) Cuatrocapaite-(NH4) and cuatrocapaite-(K), two new minerals from the Torrecillas mine, Iquique Province, Chile, related to lucabindiite and gajardoite. Mineralogical Magazine, 83 (5) 741-748 doi:10.1180/mgm.2019.26
Classification of Cuatrocapaite-(NH4)
3.DC.
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
3 : HALIDES
D : Oxyhalides, hydroxyhalides and related double halides
C : With Pb (As,Sb,Bi), without Cu
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Ctc-NH4 | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Physical Properties of Cuatrocapaite-(NH4)
Vitreous
Transparency:
Transparent
Comment:
vitreous, pearly, silky (vein-fillings), dull (powdery)
Colour:
Colorless to white
Streak:
White
Hardness:
2½ on Mohs scale
Comment:
ca.
Tenacity:
Flexible
Cleavage:
Perfect
on {001}
on {001}
Comment:
not elastic
Density:
2.65(2) g/cm3 (Measured) 2.667 g/cm3 (Calculated)
Optical Data of Cuatrocapaite-(NH4)
Type:
Uniaxial (-)
RI values:
nω = 1.779(3) nε = 1.541(3)
Max. Birefringence:
δ = 0.238
Based on recorded range of RI values above.
Based on recorded range of RI values above.
Interference Colours:
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
The colours simulate birefringence patterns seen in thin section under crossed polars. They do not take into account mineral colouration or opacity.
Michel-Levy Bar The default colours simulate the birefringence range for a 30 µm thin-section thickness. Adjust the slider to simulate a different thickness.
Grain Simulation You can rotate the grain simulation to show how this range might look as you rotated a sample under crossed polars. Each grain retains its interference colour (retardation) while its brightness falls to black at extinction and reaches a maximum between extinction positions.
Surface Relief:
Moderate
Pleochroism:
Non-pleochroic
Chemistry of Cuatrocapaite-(NH4)
Mindat Formula:
(NH4)3(NaMg◻)(As2O3)6Cl6 · 16H2O
Element Weights:
Crystallography of Cuatrocapaite-(NH4)
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
R3m
Setting:
R3m
Cell Parameters:
a = 5.25321(19) Å, c = 46.6882(19) Å
Ratio:
a:c = 1 : 8.888
Unit Cell V:
1115.8 ų
Z:
1
Morphology:
Hexagonal tablets, to about 0.3 mm in diameter, sometimes in vermiform stacks. Also, as satin-spar-like vein-fillings and white powdery surface coatings.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 15.68 Å | (100) |
| 5.20 Å | (56) |
| 4.518 Å | (35) |
| 3.256 Å | (42) |
| 3.111 Å | (32) |
| 2.625 Å | (71) |
| 2.490 Å | (41) |
| 2.349 Å | (47) |
Reference:
Kampf, Anthony R., Chukanov, Nikita V., Möhn, Gerhard, Dini, Maurizio, Molina Donoso, Arturo A., Friis, Henrik (2019) Cuatrocapaite-(NH4) and cuatrocapaite-(K), two new minerals from the Torrecillas mine, Iquique Province, Chile, related to lucabindiite and gajardoite. Mineralogical Magazine, 83 (5) 741-748 doi:10.1180/mgm.2019.26
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47d : [Arsenates, antimonates, selenates, bismuthinates] | |
| 47g : [Halogen-bearing surface weathering minerals] | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 53 : Other minerals with taphonomic origins | <0.4 |
Type Occurrence of Cuatrocapaite-(NH4)
General Appearance of Type Material:
Aggregates of tabular hexagonal crystals; the crystals are up to ca. 0.3 mm in diameter
Place of Conservation of Type Material:
The description is based upon four cotype specimens. Three are deposited in the collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 66984, 66985 and 66986. One is deposit
Geological Setting of Type Material:
secondary alteration
Associated Minerals at Type Locality:
Reference:
Kampf, Anthony R., Chukanov, Nikita V., Möhn, Gerhard, Dini, Maurizio, Molina Donoso, Arturo A., Friis, Henrik (2019) Cuatrocapaite-(NH4) and cuatrocapaite-(K), two new minerals from the Torrecillas mine, Iquique Province, Chile, related to lucabindiite and gajardoite. Mineralogical Magazine, 83 (5) 741-748 doi:10.1180/mgm.2019.26
Synonyms of Cuatrocapaite-(NH4)
Other Language Names for Cuatrocapaite-(NH4)
Relationship of Cuatrocapaite-(NH4) to other Species
Member of:
Other Members of Lucabindiite Group:
| Cuatrocapaite-(K) | K3(NaMg◻)(As2O3)6Cl6 · 16H2O | Trig. 3m(32/m) : R3m |
| Ermakovite | (NH4)(As2O3)2Br | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Gajardoite | KCa0.5As3+4O6Cl2 · 5H2O | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Gajardoite-(NH4) | (NH4)As3+4O6Cl2(Ca0.5◻0.5)(H2O)5 | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Lucabindiite | (K,NH4)As4O6(Cl,Br) | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Mauriziodiniite | (NH4)(As2O3)2I | Hex. 6/mmm(6/m2/m2/m) : P6/mmm |
| Russoite | (NH4)ClAs2O3(H2O)0.5 | Hex. 622 : P622 |
| Torrecillasite | Na(As,Sb)3+4O6Cl | Orth. |
Related Minerals - Strunz-mindat Grouping
| 3.DC. | Gajardoite | KCa0.5As3+4O6Cl2 · 5H2O |
| 3.DC. | Lucabindiite | (K,NH4)As4O6(Cl,Br) |
| 3.DC. | Cuatrocapaite-(K) | K3(NaMg◻)(As2O3)6Cl6 · 16H2O |
| 3.DC. | Napoliite | Pb2OFCl |
| 3.DC. | Torrecillasite | Na(As,Sb)3+4O6Cl |
| 3.DC.05 | Paralaurionite | PbCl(OH) |
| 3.DC.05 | Laurionite | PbCl(OH) |
| 3.DC.05 | Mauriziodiniite | (NH4)(As2O3)2I |
| 3.DC.05 | Russoite | (NH4)ClAs2O3(H2O)0.5 |
| 3.DC.10 | Fiedlerite | Pb3FCl4(OH) · H2O |
| 3.DC.15 | Penfieldite | Pb2Cl3(OH) |
| 3.DC.15 | Telluroperite | Pb3TeO4Cl2 |
| 3.DC.20 | Laurelite | Pb7F12Cl2 |
| 3.DC.25 | Zhangpeishanite | BaFCl |
| 3.DC.25 | Matlockite | PbFCl |
| 3.DC.25 | Zavaritskite | (BiO)F |
| 3.DC.25 | Rorisite | CaFCl |
| 3.DC.25 | Bismoclite | BiOCl |
| 3.DC.25 | Vegrandisite | BaCl2 |
| 3.DC.30 | Nadorite | PbSbClO2 |
| 3.DC.30 | Perite | PbBiClO2 |
| 3.DC.40 | Thorikosite | Pb3Cl2(OH)(SbO3,AsO3) |
| 3.DC.45 | Mereheadite | Pb47Cl25(OH)13O24(CO3)(BO3)2 |
| 3.DC.50 | Blixite | Pb8O5(OH)2Cl4 |
| 3.DC.52 | Rumseyite | Pb2OClF |
| 3.DC.55 | Vladkrivovichevite | [Pb32O18][Pb4Mn2O]Cl14(BO3)8 · 2H2O |
| 3.DC.55 | Pinalite | Pb3WO5Cl2 |
| 3.DC.57 | Yeomanite | Pb2O(OH)Cl |
| 3.DC.60 | Symesite | Pb10(SO4)O7Cl4 · H2O |
| 3.DC.60 | 'Lorettoite' | Pb7O6Cl2 |
| 3.DC.62 | 'Sarawakite (of Frenzel)' | Sb, O, Cl (?) |
| 3.DC.65 | Ecdemite | Pb6As3+2O7Cl4 |
| 3.DC.70 | Mendipite | Pb3Cl2O2 |
| 3.DC.75 | Damaraite | Pb3Cl(OH)O2 |
| 3.DC.80 | Onoratoite | Sb8Cl2O11 |
| 3.DC.95 | Barstowite | Pb4Cl6(CO3) · H2O |
Other Information
Notes:
At room temperature, not readily soluble in water or acids (including concentrated HCl, H2SO4 and HNO3); rapidly decomposes in aqueous solution of NaOH forming a nearly transparent residue of Mg(OH)2.
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 Cuatrocapaite-(NH4)
mindat.org URL:
https://www.mindat.org/min-53209.html
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References for Cuatrocapaite-(NH4)
Reference List:
Hålenius, Ulf, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2018) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) NEWSLETTER 46. European Journal of Mineralogy, 30 (6) 1181-1189 doi:10.1127/ejm/2018/0030-2819
Kampf, Anthony R., Chukanov, Nikita V., Möhn, Gerhard, Dini, Maurizio, Molina Donoso, Arturo A., Friis, Henrik (2019) Cuatrocapaite-(NH4) and cuatrocapaite-(K), two new minerals from the Torrecillas mine, Iquique Province, Chile, related to lucabindiite and gajardoite. Mineralogical Magazine, 83 (5) 741-748 doi:10.1180/mgm.2019.26
Localities for Cuatrocapaite-(NH4)
Showing 1 localities.
symbol to view information about a locality.
The Locality List
- 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).
All localities listed without proper references should be considered as questionable.
Chile (TL) | |
| Kampf et al. (2019) +1 other reference |
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Torrecillas mine, Iquique, Iquique Province, Tarapacá, Chile