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Almeidaite

Pictures (2 Images total)

Almeidaite
Views (File:
1441429139
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Almeidaite
Locality: Unnamed deposit, Novo Horizonte, Bahia, Brazil; Dimensions: 2 cm x 1.5 cm x 0.7 cm; A very recently discovered new species that has been approved by the IMA this year. The sample, a flattened crystal with very well defined faces and edges, gray color with brownish shades and a good luster, was personally collected by Luiz Menezes, first author of the article that describes the species. This specimen was published on the Mineralogical Record´s web page, in the ‘What’s New in the Mineral World?’ section, report #35, August 14, 2013 edition. Novo Horizonte, Bahía, Brazil; Found in 04/2013; Specimen size: 2 × 1.5 × 0.7 cm = 0.8” × 0.6” × 0.3”
Copyright: Fabre Minerals; Contribution: Stefan
Location: Brasilien/Nordosten (Região Nordeste)/Bahia/Novo Horizonte/Unbenanntes Vorkommen
Mineral: Almeidaite
Image: 1441429139
License: Usage for Mineralienatlas project only
Almeidaite

Locality: Unnamed deposit, Novo Horizonte, Bahia, Brazil; Dimensions: 2 cm x 1.5 cm x 0.7 cm; A very recently discovered new species that has been approved by the IMA this year. The sample, a flatt...
Copyright: Fabre Minerals
Contribution: Stefan 2015-09-05
Locality: Unbenanntes Vorkommen / Novo Horizonte / Bahia / Nordosten (Região Nordeste) / Brasilien
Almeidait
Views (File:
1484582431
): 696
Almeidait
Schwarzbrauner Kristall von Almeidait, 12 x 11 x 4 mm. Fundort: Novo Horizonte, Bahia, Brasilien
Copyright: Yi Sun; Contribution: sun-mineral
Collection: Yi Sun
Location: Brasilien/Nordosten (Região Nordeste)/Bahia/Novo Horizonte
Mineral: Almeidaite
Image: 1484582431
License: Usage for Mineralienatlas project only
Almeidait

Schwarzbrauner Kristall von Almeidait, 12 x 11 x 4 mm. Fundort: Novo Horizonte, Bahia, Brasilien
Collection: Yi Sun
Copyright: Yi Sun
Contribution: sun-mineral 2017-01-16
Locality: Novo Horizonte / Bahia / Nordosten (Região Nordeste) / Brasilien

Collectors Summary

Color schwarz
Streak color braun
Lustre Halbmetallglanz
Crystal System trigonal, R3
Morphology einzelne abgeflachte Kristalle; abgeflacht auf [0001]; Größe bis 30x30x6mm; dominiert vom Basispinakoid {0001} die von verschiedenen, meist steilen, Rhomboedern und dem hexagonalem Prisma {1120} begrenzt wird. Die meisten der Kristalle sind mehrfach verzwillingt, mit nicht-ebenen Berührungsflächen, die annähernd parallel zu der c-Achse sind.

Additional information / Summary

Almeidaite ist ein Mitglied der Crichtonit-Gruppe mit Pb dominant in der A-Stelle (mit 12-facher Koordination) und Zn dominant auf der T-Seite (bei 4-fach-Koordination). Es ist eine Zn Analog von Senait und ein Pb Analog von Landauit.

Chemism

Chemical formula

PbZn2(Mn,Y)(Ti,Fe3+)18O36(OH,O)2

Empirical formula (analysis)

(Pb0.59Sr0.12Ca0.04La0.03)Σ0.78(Mn0.54Y0.46)Σ1.00Zn1.43(Ti13.02Fe3+4.98)Σ18.00(Fe3+0.32Mn0.15)Σ0.47 [O37.18(OH)0.82]Σ38.00

Additional chem. information

Crichtonit-Gruppe

Chemical composition

Blei, Eisen, Mangan, Titan, Yttrium, Zink, Sauerstoff, Wasserstoff

Unit weight: 1838.892168491 u; Number of atoms in the formula: 60.5

Info

Empirical formula:

(Pb0.59Sr0.12Ca0.04La0.03)(Mn0.54Y0.46)Zn1.43(Ti13.02Fe4.98)(Fe0.32Mn0.15)[O37.18(OH)0.82]

Element

Symbol

Weight%

Atoms

Atoms%

Atom weight (u)

Sum weight (u)
Hydrogen

H

0.04

0.82

1.36

1.0079470

0.8265165
Oxygen

O

33.06

38

62.81

15.9994300

607.9783400
Calcium

Ca

0.09

0.04

0.07

40.0784000

1.6031360
Titanium

Ti

33.89

13.02

21.52

47.8671000

623.2296420
Manganese

Mn

2.06

0.69

1.14

54.9380499

37.9072544
Iron

Fe

16.10

5.3

8.76

55.8452000

295.9795600
Zinc

Zn

5.09

1.43

2.36

65.4094000

93.5354420
Strontium

Sr

0.57

0.12

0.20

87.6210000

10.5145200
Yttrium

Y

2.22

0.46

0.76

88.9058520

40.8966919
Lanthanum

La

0.23

0.03

0.05

138.9055200

4.1671656
Lead

Pb

6.65

0.59

0.98

207.2100000

122.2539000

Strunz 9th edition incl. updates

4.CC.40

4: Oxide, Hydroxide (Oxide, Hydroxide, V[5,6]-Vanadate, Arsenite, Antimonite, Bismutite, Sulfite, Selenite, Tellurite, Iodate)
C: Metall: Sauerstoff = 2: 3,3: 5, und vergleichbare
C: Mit großen und mittelgroßen Kationen
40:Crichtonit-Gruppe

Lapis Classification

IV/C.09-055

IV: OXIDE
C: Oxide mit Verhältnis Metall : Sauerstoff = 2:3 (M2O3 und verwandte Verbindungen)
9: Crichtonit-Gruppe

IMA status

anerkannt - CNMNC Newsletter No. 16, August 2013

Mineral status

anerkanntes Mineral

IMA Classification

IMA Classification

 Crichtonite Group

Optical Properties

Color

schwarz

Streak color

braun

Diaphaneity (Transparency)

opak

Lustre

Halbmetallglanz

Reflectivity: (Lambda nm) ↓, ↑, Ø

(470) 12.78, 15.39, 14.09
(546) 12.86, 15.43, 14.15
(589) 12.91, 15.55, 14.23
(650) 13.04, 15.75, 14.40
Reflection chart Almeidaite

Reflectivity Ø

14.22

Crystallography

Crystal System

trigonal

Class (H-M)

3

Space Group number

148

Space Group

R3

Cell parameters a (Å)

10.4359

Cell parameters b (Å)

-

Cell parameters c (Å)

21.0471

Cell parameters a/b or c/a

2.017

Cell parameters c/b

-

Z

3

Volume (ų)

1985.101

X-Ray Powder Diffraction

3.436(48), 3.074(50), 3.023(50), 2.907(100), 2.781(44), 2.492(55), 2.157(55), 1.615(50)
XRD chart Almeidaite

Calculated from d-spacing and intensity at 0.1541838 nm (Cu)

Morphology

einzelne abgeflachte Kristalle; abgeflacht auf [0001]; Größe bis 30x30x6mm; dominiert vom Basispinakoid {0001} die von verschiedenen, meist steilen, Rhomboedern und dem hexagonalem Prisma {1120} begrenzt wird. Die meisten der Kristalle sind mehrfach verzwillingt, mit nicht-ebenen Berührungsflächen, die annähernd parallel zu der c-Achse sind.

Crystals 3D

Open larger view

Crystal Structure 3D

Open larger view

Physical Properties

Density (g/cm³)

4.61 (berechnet)

4.614 ( ρ calc. Mineralienatlas )

(Co-)Type locality

(Co-)Type locality

Brasilien/Nordosten (Região Nordeste)/Bahia/Novo Horizonte/Unbenanntes Vorkommen

Brasilien/Nordosten (Região Nordeste)/Bahia/Novo Horizonte/Mula Mine

Type material

Museu de Geociências, Instituto de Geociências, Universidade de São Paulo, São Paulo, Brazilien

Collection number of type material

DR744

Preface

Name from

Professor Fernando Flávio Marques de Almeida (1916–2013)

Author (Name, Year)

Luiz A.D. Menezes Filho, Nikita V. Chukanov, Ramiza K. Rastsvetaeva, Sergey M. Aksenov, Igor V. Pekov, Mário L.S.C. Chaves, Ricardo Scholz, Daniel Atencio, Paulo R.G. Brandão, Antônio W. Romano, Luiz C.A. de Oliveira, José D. Ardisson, Klaus Krambrock, Ro

References

Luiz A.D. Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., Chaves, M.L.S.C., Scholz, R., Atencio, D., Brandão, P.R.G., Romano, A.W., de Oliveira, L.C.A., Ardisson, J.D., Krambrock, K., Moreira, R.L., Guimarães, F.S., Persiano, A.C. and Richards, R.P. (2013) Almeidaite, IMA 2013-020. CNMNC Newsletter No. 16, 2013, page 2705; Mineralogical Magazine, 77, 2695-2709.

Menezes Filho, L.A.D., Chukanov, N.V., Rastsvetaeva, R.K., Aksenov, S.M., Pekov, I.V., Chaves, M.L.S.C., Scholz, R., Atencio, D., Brandão, P.R.G., Romano, A.W., de Oliveira, L.C.A., Ardisson, J.D., Krambrock, K., Moreira, R.L., Guimarães, F.S., Persiano, A.C., Richards, R.P.(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, (in press).

IMA group assignments

 
Crichtonite Group
 
 
 

 
 
Almeidaite
PbZn2(Mn,Y)(Ti,Fe3+)18O36(OH,O)2
trigonal
R3

 
 
Antipinite
KNa3Cu2(C2O4)4
triklin
P1

 
 
Botuobinskite
SrFe2+(Ti4+12Cr3+6)Mg2[O36(OH)2]
trigonal
R3

 
 
Cleusonite
(Pb,Sr)(U4+,U6+)(Fe2+,Zn)2(Ti,Fe2+,Fe3+)18(O,OH)38
trigonal
R3

 
 
Crichtonite
(Sr,Pb)(Mn,Fe)Fe3+2(Ti,Fe3+)18O38
trigonal
R3

 
 
Davidite-(Ce)
(Ce,La,U,Y)2Fe3+2(Ti,Fe3+)18O38
trigonal
R3

 
 
Davidite-(La)
La(Y,U)Fe2(Ti,Fe,Cr,V)18(O,OH,F)38
trigonal
R3

 
 
Dessauite-(Y)
(Sr,Pb)(Y,U)Fe3+2(Ti,Fe3+)18O38
trigonal
R3

 
 
Gramaccioliite-(Y)
(Pb,Sr)(Y,Mn)(Fe3+)2(Ti,Fe3+)18O38
trigonal
R3

 
 
Landauite
(Na,Pb)(Mn2+,Y)(Zn,Fe)2(Ti,Fe3+,Nb)18(O,OH,F)O38
trigonal
R3

 
 
Lindsleyite
(BaSr)Zr(Fe3+,Mg)2(Ti,Cr,Fe3+)18O38
trigonal
R3

 
 
Loveringite
(Ca,Ce)(Zr,Mg)(Ti,Fe3+)2(Ti,Cr,Fe3+)18O38
trigonal
R3

 
 
Mapiquiroite
(Sr,Pb)(U,Y)Fe2(Ti,Fe3+,Cr3+)18O38
trigonal
R3

 
 
Mathiasite
K(Zr,Ca)(Fe3+,Mg)2(Ti,Cr,Fe3+)18O38
trigonal
R3

 
 
Mianningite
(☐,Pb,Ce,Na)(U4+,Mn,U6+)Fe3+2(Ti,Fe3+)18O38
trigonal
R3

 
 
Mirnyite
SrZr4+(Ti4+12Cr3+6)Mg2O38
trigonal
R3

 
 
Paseroite
PbMn2+(Mn2+,Fe2+)2(V5+,Ti,Fe3+,☐)18O38
triklin
R3

 
 
Romanite ?
(Fe2+,U,Pb)2(Ti,Fe3+)O4
 
 

 
 
Saranovskite
SrCaFe2+2(Cr4Ti2)Ti12O38
trigonal
R3

 
 
Senaite
Pb(Mn,Y,U)(Fe,Zn)2(Ti,Fe,Cr,V)18(O,OH)38
trigonal
R3

 
 
Unnamed (HBU UK-4)
NaFe2+Zn2(Ti,Fe3+,Nb)6Ti12O38
trigonal
R3

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Actuality: 03. Oct 2024 - 11:22:00

Other languages

German

Almeidait

English

Almeidaite

Russian

Алмейдаит

CNMNC (IMA)-Number

IMA 2013-020

CNMNC symbol

Symbol

Amd

Locations with GPS information

IDs

GUSID (Global unique identifier short form) k1y2-RSFJ0ac08zPIuwJGg
GUID (Global unique identifier) F9B65C93-8514-4627-9CD3-CCCF22EC091A
Database ID 7583