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Braccoite

A valid IMA mineral species

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Edit Braccoite Add Synonym Edit CIF structures Clear Cache

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Braccoite

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

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About BraccoiteHide

Roberto Bracco

Formula:

NaMn²⁺₅[Si₅As⁵⁺O₁₇(OH)](OH)

Colour:

Brown-red

Lustre:

Vitreous, Resinous

Specific Gravity:

3.56 (Calculated)

Crystal System:

Triclinic

Name:

Named by F. Cámara, E. Bittarello, M.E. Ciriotti, F. Nestola, F. Radica, and M. Marchesini in 2015 in honour of Dr Roberto Bracco (b. 1959), a systematic minerals collector with a special interest in manganese minerals.

Type Locality:

ⓘ Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

The As analogue of saneroite, which is topologically identical.
Chemically somewhat similar to johninnesite (which has essential Mg) and to arsenmedaite (which has no Na).

The structure details: (1) five-repeat single isolated chains of SiO₄ tetrahedra, with sixth tetrahedron as an appendix; (2) layer of tet‑
rahedra || (111) formed by lateral repeat of chains by a center of symmetry; (3) 5 octahedral sites (Mn) form a band || two single chains of tetrahedra (above and below); (4) channels, laterally separating the bands, partially occupied by two independent Na atoms.

Unique IdentifiersHide

Mindat ID:

46006

Long-form identifier:

mindat:1:1:46006:8

IMA Classification of BraccoiteHide

IMA status:

Approved

IMA Formula:

NaMn²⁺₅[Si₅O₁₄(OH)](As⁵⁺O₃OH)

Approval year:

2013

First published:

2015

Classification of BraccoiteHide

Strunz-mindat (2026):

9.DO.

9 : SILICATES (Germanates)
D : Inosilicates
O : Inosilicates with 7-, 8-, 10-, 12- and 14-periodic chains

Mineral SymbolsHide

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
Bcc	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 BraccoiteHide

Lustre:

Vitreous, Resinous

Transparency:

Translucent

Colour:

Brown-red

Streak:

Pale yellow

Comment:

Could not be measured due to size and intergrowth with tiragalloite

Tenacity:

Brittle

Cleavage:

None Observed

Fracture:

Irregular/Uneven

Density:

3.56 g/cm³ (Calculated)

Comment:

Couldn't be measured for the same reason as hardness

Optical Data of BraccoiteHide

Type:

Biaxial (+)

RI values:

n_α = 1.749(1) n_β = 1.750(1) n_γ = 1.760(1)

2V:

Measured: 26° (2), Calculated: 35°

Max. Birefringence:

δ = 0.011
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.

Thickness: 30 µm

Rotation:

Surface Relief:

Moderate

Pleochroism:

Weak

Comments:

Brownish-yellow (X), dark yellow (Y), yellow (Z)

Chemistry of BraccoiteHide

Mindat Formula:

NaMn²⁺₅[Si₅As⁵⁺O₁₇(OH)](OH)

Element Weights:

Element	% weight
O	37.116 %
Mn	33.538 %
Si	17.146 %
As	9.148 %
Na	2.807 %
H	0.246 %

Calculated from ideal end-member formula.

Elements listed:

As, H, Mn, Na, O, Si - search for minerals with similar chemistry

Common Impurities:

Mn(III),Mg,V

Crystallography of BraccoiteHide

Crystal System:

Triclinic

Class (H-M):

1 - Pedial

Space Group:

Cell Parameters:

a = 9.740(6) Å, b = 9.900(7) Å, c = 9.085(6) Å
α = 92.06(5)°, β = 117.41(5)°, γ = 105.27(5)°

Ratio:

a:b:c = 0.984 : 1 : 0.918

Unit Cell V:

740.37 Å³

Comment:

Different space group from ima and abs of type description

Crystal StructureHide

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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure

ID	Species	Reference	Link	Year	Locality	Pressure (GPa)	Temp (K)
0020722	Braccoite	Camara F, Bittarello E, Ciriotti M E, Nestola F, Radica F, Marchesini M (2015) As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: II. braccoite, NaMn5[Si5AsO17(OH)](OH), description and crystal structure Mineralogical Magazine 79 171-189		2015	Valletta mine, Maira Valley, Piedmont, Italy	0	293

CIF Raw Data - click here to close

data_global
_chemical_name_mineral 'Braccoite'
loop_
_publ_author_name
'Camara F'
'Bittarello E'
'Ciriotti M E'
'Nestola F'
'Radica F'
'Marchesini M'
_journal_name_full 'Mineralogical Magazine'
_journal_volume 79 
_journal_year 2015
_journal_page_first 171
_journal_page_last 189
_publ_section_title
;
 As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy:
 II. braccoite, NaMn5[Si5AsO17(OH)](OH), description and crystal structure
;
_database_code_amcsd 0020722
_chemical_compound_source 'Valletta mine, Maira Valley, Piedmont, Italy'
_chemical_formula_sum 'Na2.12 Mn9.56 Mg.38 Ca.02 V.32 Al.02 Si10.74 As.96 O38 H3.96 F.04'
_cell_length_a 9.7354
_cell_length_b 9.9572
_cell_length_c 9.0657
_cell_angle_alpha 92.691
_cell_angle_beta 117.057
_cell_angle_gamma 105.323
_cell_volume 740.370
_exptl_crystal_density_diffrn      3.560
_symmetry_space_group_name_H-M 'P -1'
loop_
_space_group_symop_operation_xyz
  'x,y,z'
  '-x,-y,-z'
loop_
_atom_site_label
_atom_site_fract_x
_atom_site_fract_y
_atom_site_fract_z
_atom_site_occupancy
_atom_site_U_iso_or_equiv
Na1   0.50000   0.00000   0.50000   1.00000   0.03000
Na2   0.19120   0.53400   0.44320   0.56000   0.01510
Mn1   0.74388   0.97982   0.29542   0.98000   0.01168
Mg1   0.74388   0.97982   0.29542   0.01000   0.01168
Ca1   0.74388   0.97982   0.29542   0.01000   0.01168
Mn2   0.99723   0.21282   0.22004   0.94000   0.01045
Mg2   0.99723   0.21282   0.22004   0.06000   0.01045
Mn3   0.86298   0.88807   0.02950   0.88000   0.00981
Mg3   0.86298   0.88807   0.02950   0.10000   0.00981
V3   0.86298   0.88807   0.02950   0.01000   0.00981
Al3   0.86298   0.88807   0.02950   0.01000   0.00981
Mn4   0.57398   0.66844   0.09774   0.99000   0.00999
Mg4   0.57398   0.66844   0.09774   0.01000   0.00999
Mn5   0.71912   0.55370   0.85346   0.99000   0.01242
Mg5   0.71912   0.55370   0.85346   0.01000   0.01242
Si1   0.87449   0.27556   0.82439   1.00000   0.00920
Si2   0.03102   0.23894   0.60955   1.00000   0.00861
Si3   0.20746   0.54939   0.77372   1.00000   0.00943
Si4   0.47814   0.75745   0.73037   1.00000   0.00925
Si5   0.61959   0.07757   0.89560   1.00000   0.00829
Si6   0.60697   0.71401   0.48355   0.37000   0.00903
As6   0.60697   0.71401   0.48355   0.48000   0.00903
V6   0.60697   0.71401   0.48355   0.15000   0.00903
O1   0.70480   0.16540   0.79470   1.00000   0.01320
O2   0.88530   0.22670   0.65670   1.00000   0.01450
O3   0.11100   0.40940   0.62040   1.00000   0.01330
O4   0.30220   0.66920   0.70620   1.00000   0.01240
O5   0.49870   0.92650   0.75290   1.00000   0.01280
O6   0.46450   0.71140   0.54650   1.00000   0.01420
O7   0.85560   0.43310   0.82220   1.00000   0.01440
O8   0.96450   0.72480   0.00810   1.00000   0.01180
O9   0.95350   0.15320   0.42200   1.00000   0.01230
O10   0.82870   0.81300   0.24690   1.00000   0.01100
O11   0.08050   0.60580   0.80350   1.00000   0.01430
O12   0.66490   0.49180   0.05940   1.00000   0.01140
O13   0.37460   0.27650   0.11810   1.00000   0.01130
O14   0.49610   0.14800   0.91020   1.00000   0.01270
O15   0.24040   0.94900   0.93670   1.00000   0.01120
O16   0.68090   0.88070   0.47500   1.00000   0.01480
O17   0.51720   0.60420   0.29770   1.00000   0.01370
O18   0.25680   0.34690   0.36990   1.00000   0.01490
O19   0.08970   0.05020   0.17280   1.00000   0.01340
H7   0.93700   0.49300   0.82000   1.00000   0.01700
H19   0.17900   0.05000   0.27600   0.98000   0.01600
F19   0.17900   0.05000   0.27600   0.02000   0.01600
loop_
_atom_site_aniso_label
_atom_site_aniso_U_11
_atom_site_aniso_U_22
_atom_site_aniso_U_33
_atom_site_aniso_U_12
_atom_site_aniso_U_13
_atom_site_aniso_U_23
Na1 0.04870 0.03800 0.02150 0.02800 0.02300 0.01750
Na2 0.02330 0.01300 0.00870 0.00320 0.00900 0.00230
Mn1 0.00980 0.01070 0.01280 0.00149 0.00516 0.00090
Mg1 0.00980 0.01070 0.01280 0.00149 0.00516 0.00090
Ca1 0.00980 0.01070 0.01280 0.00149 0.00516 0.00090
Mn2 0.01030 0.01070 0.01040 0.00265 0.00545 0.00342
Mg2 0.01030 0.01070 0.01040 0.00265 0.00545 0.00342
Mn3 0.00980 0.00930 0.01120 0.00304 0.00566 0.00310
Mg3 0.00980 0.00930 0.01120 0.00304 0.00566 0.00310
V3 0.00980 0.00930 0.01120 0.00304 0.00566 0.00310
Al3 0.00980 0.00930 0.01120 0.00304 0.00566 0.00310
Mn4 0.00930 0.00910 0.01110 0.00244 0.00485 0.00261
Mg4 0.00930 0.00910 0.01110 0.00244 0.00485 0.00261
Mn5 0.01250 0.01130 0.01530 0.00397 0.00813 0.00284
Mg5 0.01250 0.01130 0.01530 0.00397 0.00813 0.00284
Si1 0.00870 0.01020 0.01010 0.00310 0.00550 0.00400
Si2 0.00850 0.00920 0.00790 0.00250 0.00390 0.00270
Si3 0.00860 0.00880 0.01100 0.00210 0.00500 0.00390
Si4 0.00970 0.00900 0.00930 0.00250 0.00490 0.00380
Si5 0.00810 0.00910 0.00860 0.00290 0.00440 0.00380
Si6 0.00980 0.00979 0.00859 0.00275 0.00542 0.00280
As6 0.00980 0.00979 0.00859 0.00275 0.00542 0.00280
V6 0.00980 0.00979 0.00859 0.00275 0.00542 0.00280
O1 0.01070 0.01530 0.01420 0.00240 0.00720 0.00710
O2 0.01180 0.02200 0.01130 0.00530 0.00690 0.00430
O3 0.01590 0.01020 0.01040 0.00160 0.00490 0.00200
O4 0.01120 0.01310 0.01290 0.00200 0.00650 0.00520
O5 0.01380 0.00870 0.01210 0.00120 0.00450 0.00360
O6 0.01290 0.01990 0.00990 0.00370 0.00640 0.00320
O7 0.01340 0.01080 0.02140 0.00420 0.01010 0.00580
O8 0.01120 0.01320 0.01120 0.00560 0.00460 0.00340
O9 0.01370 0.01340 0.00870 0.00220 0.00560 0.00190
O10 0.01070 0.01210 0.00910 0.00400 0.00360 0.00230
O11 0.01480 0.01400 0.02000 0.00630 0.01200 0.00690
O12 0.01150 0.01140 0.01030 0.00350 0.00440 0.00380
O13 0.01280 0.01200 0.01030 0.00510 0.00590 0.00400
O14 0.01280 0.01400 0.01420 0.00620 0.00780 0.00470
O15 0.01150 0.01100 0.01040 0.00340 0.00480 0.00440
O16 0.01750 0.01300 0.01360 0.00310 0.00810 0.00480
O17 0.01420 0.01420 0.01050 0.00170 0.00600 0.00030
O18 0.01330 0.01590 0.01650 0.00680 0.00660 0.00690
O19 0.01250 0.01530 0.01120 0.00490 0.00440 0.00340

X-Ray Powder DiffractionHide

Powder Diffraction Data:

d-spacing	Intensity
3.042 Å	(57)
3.005 Å	(61)
2.973 Å	(82)
2.821 Å	(100)
2.696 Å	(87)
2.614 Å	(29)
1.673 Å	(30)

Locality:

Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

Comments:

From Type Description.

Geological EnvironmentHide

Paragenetic Mode(s):

Paragenetic Mode	Earliest Age (Ga)
High-? alteration and/or metamorphism
32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits
Stage 7: Great Oxidation Event	<2.4
47d : [Arsenates, antimonates, selenates, bismuthinates]

Type Occurrence of BraccoiteHide

Type Locality:

ⓘ Valletta Mine, Vallone della Valletta, Canosio, Cuneo Province, Piedmont, Italy

General Appearance of Type Material:

subhedral crystals (a few hundred microns across) in brown-red coloured thin masses a few centrimeters in size

Place of Conservation of Type Material:

Type material is deposited in the mineralogical collections of the Museo Regionale di Scienze Naturali di Torino, Sezione di Mineralogia, Petrografia e Geologia, Torino, Italy, catalogue number M/15939

Associated Minerals at Type Locality:

Gamagarite	Hematite	Manganberzeliite	Palenzonaite	Quartz
Saneroite	Tiragalloite	Tokyoite

Synonyms of BraccoiteHide

IMA2013-093

Other Language Names for BraccoiteHide

Dutch:Braccoiet

German:Braccoit

Common AssociatesHide

Associations Based on Photo Data:

2 photos of Braccoite associated with Hematite

Fe₂O₃

Related Minerals - Strunz-mindat Grouping Hide

9.DO.	Illoqite-(Ce)	Na₂NaBaCeZnSi₆O₁₇	Orth. mmm(2/m2/m2/m) : Pcca
9.DO.05	Pyroxferroite	(Fe,Mn,Ca)SiO₃	Tric.
9.DO.05	Pyroxmangite	Mn²⁺SiO₃	Tric. 1 : P1
9.DO.10	Pellyite	Ba₂CaFe²⁺₂Si₆O₁₇	Orth. mmm(2/m2/m2/m)
9.DO.15	Manganonordite-(Ce)	Na₃SrCeMn²⁺Si₆O₁₇	Orth. mmm(2/m2/m2/m) : Pcca
9.DO.15	Ferronordite-(Ce)	Na₃SrCeFe²⁺Si₆O₁₇	Orth. mmm(2/m2/m2/m) : Pcca
9.DO.15	Nordite-(Ce)	(Ce,La)(Sr,Ca)Na₂(Na,Mn)(Zn,Mg)Si₆O₁₇	Orth. mmm(2/m2/m2/m) : Pcca
9.DO.15	Nordite-(La)	(La,Ce)(Sr,Ca)Na₂(Na,Mn)(Zn,Mg)Si₆O₁₇	Orth. mmm(2/m2/m2/m) : Pcca
9.DO.15	Ferronordite-(La)	Na₃Sr(La,Ce)FeSi₆O₁₇	Orth.
9.DO.15	Meieranite	Na₂Sr₃MgSi₆O₁₇	Orth.
9.DO.20	Alamosite	PbSiO₃	Mon. 2/m : P2/m
9.DO.25	Liebauite	Ca₃Cu₅Si₉O₂₆	Mon. 2/m : B2/b
9.DO.30	Vladykinite	Na₃Sr₄(Fe²⁺Fe³⁺)Si₈O₂₄	Mon. 2/m : P2₁/b
9.DO.30	Rundqvistite-(Ce)	Na₃(Sr₃Ce)[Zn₂Si₈O₂₄]	Mon. 2/m : P2₁/b

Fluorescence of BraccoiteHide

In UV light:

none

Other InformationHide

Notes:

Raman bands [cm^-1]: ~829, 907, 932, 706w, 748w (SiO₄ and AsO₄ groups); overlapping bands centered at 3361 and 3507 (OH stretching)

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 BraccoiteHide

mindat.org URL:

https://www.mindat.org/min-46006.html
Please feel free to link to this page.

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External Links:

Look for Braccoite on Webmineral

Look for Braccoite on Wikipedia

Look for Braccoite on Mineralien Atlas

Raman and XRD data at RRUFF project

References and PDF downloads at RRUFF project

American Mineralogist Crystal Structure Database

Handbook of Mineralogy page PDF

Mineral Dealers:

Buy from D. Joyce minerals

References for BraccoiteHide

Reference List:

Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2013) New minerals and nomenclature modifications approved in 2013. CNMNC Newsletter No 18. Mineralogical Magazine, 77 (8) 3249-3258 doi:10.1180/minmag.2013.077.8.15

Cámara, Fernando, Bittarello, Erica, Ciriotti, Marco E., Nestola, Fabrizio, Radica, Francesco, Marchesini, Marco (2015) As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: II. Braccoite, NaMn^²⁺₅ [Si₅AsO₁₇(OH)](OH), description and crystal structure. Mineralogical Magazine, 79 (1) 171-189 doi:10.1180/minmag.2015.079.1.14

(2016) Braccoite. Handbook of Mineralogy. Mineralogical Society of America

Localities for BraccoiteHide

Showing 2 localities.

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.

Hide all sections | Show all sections

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.


Italy
Liguria Genoa Ne Statale ⓘ Scrava Mine (Statale Mine)	Castellaro et al. (2023)
Piedmont Cuneo Province Canosio Vallone della Valletta ⓘ Valletta Mine (TL)	Williams et al. (2013) +4 other references

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Braccoite

About BraccoiteHide

Unique IdentifiersHide

IMA Classification of BraccoiteHide

Classification of BraccoiteHide

Mineral SymbolsHide

Physical Properties of BraccoiteHide

Optical Data of BraccoiteHide

Chemistry of BraccoiteHide

Crystallography of BraccoiteHide

Crystal StructureHide

X-Ray Powder DiffractionHide

Geological EnvironmentHide

Type Occurrence of BraccoiteHide

Synonyms of BraccoiteHide

Other Language Names for BraccoiteHide

Common AssociatesHide

Related Minerals - Strunz-mindat GroupingHide

Fluorescence of BraccoiteHide

Other InformationHide

Internet Links for BraccoiteHide

References for BraccoiteHide

Localities for BraccoiteHide

Locality ListHide

Related Minerals - Strunz-mindat Grouping Hide