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Almeidaite

A valid IMA mineral species
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09239620014948732626822.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
03734200014948285636553.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
05847290014948732656903.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
09239620014948732626822.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
03734200014948285636553.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
01796000014946997032849.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
09239620014948732626822.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
03734200014948285636553.jpg
Almeidaite

Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
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About AlmeidaiteHide

06893550015193755878184.jpg
Prof. Fernando FlĂĄvio Marques de Almeida (1916-2013)
Formula:
PbZn2(Mn,Y)(Ti,Fe3+)18O37(OH,O)
Colour:
Black
Lustre:
Sub-Metallic
Specific Gravity:
4.68
Crystal System:
Trigonal
Name:
Named in 2013 by Luiz Albert Diaz Menezes Filho, L.A.D., N.V. Chukanov, Ramiza K. Rastsvetaeva, S.M. Aksenov, Igor Viktorovich Pekov, M.L.S.C. Chaves, R. Scholz, Daniel Atencio, P.R.G. Brandão, A.W. Romano, L.C.A. de Oliveira, J.D. Ardisson, K. Krambrock, R.L. Moreira, F.S. Guimarães, A.C. Persiano, and R. P. Richards in honor of Prof. Fernando Flåvio Marques de Almeida [February 18, 1916 Rio de Janeiro, Brazil - August 2, 2013 São Paulo, Brazil]. Flåvio Marques de Almeida is considered to be one of the most important Brazilian geologists. He was professor of geology at Institute for Technological Research, São Paulo about 1938-1939 until 1974. He became professor at the Institute of Geosciences, University of São Paulo, He was one of the founders of the Brazilian Society of Geology and the first chief editor of the Journal of Geology. His honors include: Vice-President of Géologique Société de France (1971); Medal Jose Bonifacio - Society Brazilian Geology (1964), Grand Cross of the National Order of Scientific Merit (1995), Doctor Honoris Causa State University of Campinas (1991), Medal of Merit Council Federal Engineering and Architecture (1995).
The Zn analogue of senaite and Pb analogue of landauite. ZnMn-analogue of cleusonite. PbZn-analogue of crichtonite. Chemically somewhat similar to neĆŸilovite.

Almeidaite is a member of the crichtonite group with Pb dominant in the A site (with 12-fold coordination, located in the cubic layer, M0) and Zn dominant in the T site (with 4-fold, i.e., tetrahedral coordination). The anionic cp (close packed) framework has 9 layers along c in the chhchh sequence.



Unique IdentifiersHide

Mindat ID:
43884
Long-form identifier:
mindat:1:1:43884:7
GUID
(UUID V4):
1c382261-3629-400e-b26c-ba733cc7dbe2

IMA Classification of AlmeidaiteHide

Classification of AlmeidaiteHide

Strunz-mindat (2024):
4.00.

4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
0 :
0 :

Mineral SymbolsHide

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

SymbolSourceReference
AmdIMA–CNMNCWarr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43

Physical Properties of AlmeidaiteHide

Lustre:
Sub-Metallic
Transparency:
Opaque
Colour:
Black
Streak:
Brown
Tenacity:
Brittle
Cleavage:
None Observed
Parting:
No parting
Fracture:
Conchoidal
Density:
4.68(5) g/cm3 (Measured)    4.616 g/cm3 (Calculated)

Optical Data of AlmeidaiteHide

Type:
Uniaxial (+)
Reflectivity:
WavelengthR1R2
400nm12.84%15.45%
420nm12.79%15.39%
440nm12.77%15.36%
460nm12.79%15.35%
470nm12.78%15.39%
480nm12.80%15.39%
500nm12.77%15.34%
520nm12.83%15.41%
540nm12.84%15.41%
546nm12.86%15.43%
560nm12.89%15.48%
580nm12.85%15.42%
589nm12.91%15.55%
600nm12.96%15.63%
620nm12.99%15.67%
640nm13.02%15.73%
650nm13.04%15.75%
660nm13.09%15.81%
680nm13.11%15.86%
700nm13.16%15.94%

Reflectance graph
Graph shows reflectance levels at different wavelengths (in nm). Top of box is 100%. Peak reflectance is 15.94%.
R1 shown in black, R2 shown in red

Chemistry of AlmeidaiteHide

Mindat Formula:
PbZn2(Mn,Y)(Ti,Fe3+)18O37(OH,O)
Elements listed:
Fe, H, Mn, O, Pb, Ti, Y, Zn - search for minerals with similar chemistry
Common Impurities:
Fe,Y,Sr,(Ca,La)

Crystallography of AlmeidaiteHide

Crystal System:
Trigonal
Class (H-M):
3 - Rhombohedral
Space Group:
R3
Cell Parameters:
a = 10.4359(2) Å, c = 21.0471(4) Å
Ratio:
a:c = 1 : 2.017
Unit Cell V:
1985.1 ų
Z:
3
Morphology:
Platy crystals flattened on [0001],dominated by the basal pinacoid {0001}, which is bounded by various, mostly steep, rhombohedra and the hexagonal prism {1120}.
Twinning:
Multiply twinned, with non-planar contact surfaces that are approximately parallel to the c axis.

Crystal StructureHide

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IDSpeciesReferenceLinkYearLocalityPressure (GPa)Temp (K)
0020510AlmeidaiteKastsvetaeva R K, Aksenov S M, Chukanov N V, Menezes L A D (2014) Crystal structure of almeidaite, a new mineral of the crichtonite group Doklady Chemistry 455 53-572014Novo Horizonte, Bahia, Brazil0293
CIF Raw Data - click here to close

X-Ray Powder DiffractionHide

Powder Diffraction Data:
d-spacingIntensity
3.436 Å(48)
3.074 Å(50)
3.023 Å(50)
2.907 Å(100)
2.781 Å(44)
2.492 Å(55)
2.157 Å(55)
1.615 Å(50)
Comments:
From Type Description.

Geological EnvironmentHide

Paragenetic Mode(s):
Paragenetic ModeEarliest Age (Ga)
Near-surface Processes
23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47)
High-𝑇 alteration and/or metamorphism
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits
Stage 4b: Highly evolved igneous rocks>3.0
35 : Ultra-alkali and agpaitic igneous rocks

Type Occurrence of AlmeidaiteHide

Type Locality:
ⓘ Unnamed deposit, Novo Horizonte district, Novo Horizonte, Bahia, Brazil
General Appearance of Type Material:
Isolated, black platy crystals up to 30 × 30 × 6 mm in size.
Place of Conservation of Type Material:
Type material is deposited in the collections of the collections of the Museu de Geociencias, Instituto de Geociencias, Universidade de SaĂ” Paulo, SaĂ” Paulo, Brazil, registration number DR744
Associated Minerals at Type Locality:
Xenotime-(Y)RutileQuartzMuscoviteKaolinite
HematiteBastnÀsite-(La)Anatase
Reference:
Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., Chaves, M.L.S.C., Richards, R.P., Atencio, D., Brandão, P.R.G., Scholz, R., Krambrock, K., Moreira, R.L., Guimarães, F.S., Romano, A.W., Persiano, A.C., de Oliveira, L.C.A., Ardisson, J.D. (2015) Almeidaite, Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2, a new crichtonite-group mineral, from Novo Horizonte, Bahia, Brazil. Mineralogical Magazine: 79: 269–283.
Download:
https://rruff.info/rruff_1.0/uploads/MM79_269.pdf

Synonyms of AlmeidaiteHide

Relationship of Almeidaite to other SpeciesHide

Member of:
Crichtonite Group
Other Members of this group:
BotuobinskiteSrFe2+Mg2(Cr3+6Ti4+12)[O36(OH)2]Trig. 3 : R3
Cleusonite(Pb,Sr)(U4+,U6+)(Fe2+,Zn)2(Ti,Fe2+,Fe3+)18(O,OH)38Trig. 3 : R3
CrichtoniteSr(Mn,Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH)38Trig. 3 : R3
Davidite-(Ce)Ce(Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH,F)38Trig. 3 : R3
Davidite-(La)La(Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH,F)38Trig. 3 : R3
Davidite-(Y)(La,Ce,Na,Ca,Pb)(Y,Fe2+,◻)(Fe2+,Mn2+)2(Ti,Fe3+,Nb,Zr)18O38 (hypothetical)Trig.
Dessauite-(Y)(Sr,Pb)(Y,U)(Ti,Fe3+)20O38Trig. 3 : R3
Gramaccioliite-(Y)(Pb,Sr)(Y,Mn)Fe3+2(Ti,Fe3+)18O38Trig. 3 : R3
Haitaite-(La)LaU4+Fe3+2(Ti13Fe2+4Fe3+)O38Trig. 3 : R3
LandauiteNaMnZn2(Ti,Fe)6Ti12O38Trig. 3 : R3
Lindsleyite(Ba,Sr)(Zr,Ca)(Fe,Mg)2(Ti,Cr,Fe)18O38Trig.
Loveringite(Ca,Ce,La)(Zr,Fe)(Mg,Fe)2(Ti,Fe,Cr,Al)18O38Trig. 3 : R3
Mapiquiroite(Sr,Pb)(U,Y)Fe2(Ti,Fe3+,Cr3+)18O38Trig. 3 : R3
Mathiasite(Mg,Cr,Fe,Ca,K)2(Ti,Zr,Cr,Fe)5O12Trig. 3 : R3
Mianningite(◻,Pb,Ce,Na)(U4+,Mn,U6+)Fe3+2 (Ti,Fe3+)18O38Trig. 3 : R3
MirnyiteSrZr4+Mg2(Cr3+6Ti4+12)O38Trig. 3 : R3
PaseroitePbMn2+(Mn2+,Fe3+)2(V5+,Ti,◻)18O38 Trig. 3 : R3
SaranovskiteSrCaFe2+2(Cr4Ti2)Ti12O38Trig. 3 : R3
SenaitePb(Mn,Y,U)(Fe,Zn)2(Ti,Fe,Cr,V)18(O,OH)38Trig. 3 : R3
UM1987-03-O:FePbTiU~(U,Pb)(Ti,Fe3+,Fe2+,Mn)21O38Trig. 3 : R3
UM2003-08-O:AlCaFeREEScTiV(Ca,Ce)Sc(Ti,V,Fe,Al)20O38
UM2006-05-O:CaFeKMnNaREESrTiZr(Sr,Na,K,REE)(Ca,Zr,Mn)(Ti,Fe)18Fe2O38
UM2006-06-O:CaFeKMnNaREESrTiZr(Sr,Na,K,REE)(Zr,Ca,Mn)(Ti,Fe)18Fe2O38
UM2006-07-O:CaFeKMnNaREESrTiZr(Na,Sr,K,REE)(Ca,Zr,Mn)(Ti,Fe)18Fe2O38
UM2006-08-O:CaFeKMnNaREESrTiZr(Na,Sr,K,REE)(Zr,Ca,Mn)(Ti,Fe)18Fe2O38
UM2006-09-O:CaFeMnREESrTiZr(Ce,Sr,REE)(Ca,Mn,Zr)Fe2(Ti,Fe)18O38
Unnamed (HBU UK-4)NaFe2+Zn2(Ti,Fe3+,Nb)6Ti12O38Trig. 3 : R3

Related Minerals - Strunz-mindat GroupingHide

4.00.Goethiteα-Fe3+O(OH)Orth. mmm (2/m 2/m 2/m)
4.00.Microlite GroupA2-mTa2X6-wZ-nIso. m3m (4/m 3 2/m) : Fd3m
4.00.Ferrotaaffeite-6N'3S(Be,Zn,Mg)FeAl4O8Trig. 3m (3 2/m) : R3m
4.00.Pyrochlore GroupA2Nb2(O,OH)6Z
4.00.PĂ­sekite-(Y)(Y,As,Ca,Fe,U)(Nb,Ti,Ta)O4
4.00.UM2004-19-O:AlCeGdZr(Gd,Ce)4Al2Zr4O17
4.00.UM2004-21-O:CaFeGdZrCa2Gd4Fe5ZrO15
4.00.UM2004-27-O:GdTiGd2Ti4O11
4.00.Mapiquiroite(Sr,Pb)(U,Y)Fe2(Ti,Fe3+,Cr3+)18O38Trig. 3 : R3
4.00.VapnikiteCa2CaUO6Mon. 2/m

Fluorescence of AlmeidaiteHide

In UV light:
Non-fluorescent in long-wave or short-wave UV

Other InformationHide

IR Spectrum:
The main absorption bands of the IR spectrum (cm-1, s = strong, sh = shoulder, w = weak) are: 3340 (O-H stretching vibrations), 1099w, 1041w, 1012w (overtones and Zn-OH bending vibrations), 695sh, 574s, 534s, 485sh (stretching vibrations in octahedra and tetrahedra).
Notes:
metamict due to trace Th;
Mössbauer spectroscopy indicates almost all Fe is trivalent
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 AlmeidaiteHide

References for AlmeidaiteHide

Reference List:
Kartashov P.M., Troneva N.V., Mokhov A.V., Kovalenko V.I., Tsareva G.M. (1993): Defective zinc-bearing senaite from Khaldzan-Buregteg rare-metal alkali granites, Mongolian Altai. Transactions (Doklady) Russ. Acad. Sci., Earth Science Section: 333A(9): 93-97.
Rastsvetaeva, R. K., Aksenov, S. M., Chukanov, N. V. (2012) Crystal structure of gĂŒnterblassite, a new mineral with a triple tetrahedral layer. Doklady Chemistry, 442 (2) 57-62 doi:10.1134/s0012500812020115
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 16. Mineralogical Magazine, 77 (6) 2695-2709 doi:10.1180/minmag.2013.077.6.01
Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., Chaves, M.L.S.C., Richards, R.P., Atencio, D., Brandão, P.R.G., Scholz, R., Krambrock, K., Moreira, R.L., Guimarães, F.S., Romano, A.W., Persiano, A.C., de Oliveira, L.C.A., Ardisson, J.D. (2015): Almeidaite, Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2, a new crichtonite-group mineral, from Novo Horizonte, Bahia, Brazil. Mineralogical Magazine: 79: 269–283.
Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., Chaves, M.L.S.C., Richards, R.P., Atencio, D., Brandão, P.R.G., Scholz, R., Krambrock, K., Moreira, R.L., Guimarães, F.S., Romano, A.W., Persiano, A.C., de Oliveira, L.C.A., Ardisson, J.D. (2015) Almeidaite, Pb(Mn,Y)Zn2(Ti,Fe3+)18O36(O,OH)2, a new crichtonite-group mineral, from Novo Horizonte, Bahia, Brazil. Mineralogical Magazine: 79: 269–283.
Belakovskiy, D.I., Uvarova, Y., Gagne, O.C. (2016) New mineral names. American Mineralogist: 101: 1012-1019.
(2023) Almeidaite. Handbook of Mineralogy. Mineralogical Society of America

Localities for AlmeidaiteHide

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 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.
Brazil
 
  • Bahia
    • Novo Horizonte
      • Novo Horizonte district
        • Tapera
Menezes (n.d.)
Williams et al. (2013) +2 other references
  • Minas Gerais
Menezes Filho et al. (2015)
Mongolia
 
  • Khovd Province
    • Myangad District
Kartashov P.M. et al. (1993)
North Macedonia
 
  • ČaĆĄka Municipality
    • NeĆŸilovo
      • Jakupica Mountains
        • Babuna Valley
Ermolaeva et al. (2017)
Chukanov et al. (2015)
Chukanov et al. (2018) +1 other reference
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