Backite
A valid IMA mineral species
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About Backite
Malcolm E. Back
Formula:
Pb2AlTeO6Cl
Colour:
Dark to pale blue-grey
Lustre:
Adamantine
Hardness:
2 - 3
Specific Gravity:
5.573 (Calculated)
Crystal System:
Trigonal
Name:
Named by K.T. Tait, V. DiCecco, M.A. Cooper, N.A. Ball, and F.C. Hawthorne in 2014 in honor of Malcolm E. Back (1951 - ), retired X-ray technician at the Royal Ontario Museum in Toronto, Canada, and author of the 2014 and 2018 editions of "Fleischer's Glossary of Mineral Species". He is currently (2021) a Research Assistant at the Museum.
New structure type.
Unique Identifiers
Mindat ID:
46057
Long-form identifier:
mindat:1:1:46057:2
GUID
(UUID V4):
(UUID V4):
75965940-60ba-41ea-a930-ae45828878c5
IMA Classification of Backite
Classification of Backite
7.BC.
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations
7 : SULFATES (selenates, tellurates, chromates, molybdates, wolframates)
B : Sulfates (selenates, etc.) with additional anions, without H2O
C : With medium-sized and large cations
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 |
|---|---|---|
| Bac | 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 Backite
Adamantine
Transparency:
Transparent
Colour:
Dark to pale blue-grey
Streak:
Very pale bluish-grey
Hardness:
2 - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
Micaceous cleavage parallel to {001}.
Micaceous cleavage parallel to {001}.
Fracture:
Splintery
Density:
5.573 g/cm3 (Calculated)
Chemistry of Backite
Mindat Formula:
Pb2AlTeO6Cl
Crystallography of Backite
Crystal System:
Trigonal
Class (H-M):
3 2 - Trapezohedral
Space Group:
P3 1 2
Setting:
P3 1 2
Cell Parameters:
a = 5.0441(7) Å, c = 9.421(2) Å
Ratio:
a:c = 1 : 1.868
Unit Cell V:
205.58 ų
Z:
1
Morphology:
Rosettes of hexagonal plates.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 4.363 Å | (55) |
| 3.959 Å | (11) |
| 3.193 Å | (100) |
| 2.521 Å | (55) |
| 2.187 Å | (17) |
| 1.978 Å | (28) |
| 1.715 Å | (20) |
| 1.555 Å | (35) |
Comments:
From Type Description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 23 : Subaerial aqueous alteration by non-redox-sensitive fluids (see also #47) | |
| High-𝑇 alteration and/or metamorphism | |
| 33 : Minerals deposited by hydrothermal metal-rich fluids (see also [#12]) |
Type Occurrence of Backite
General Appearance of Type Material:
As rosettes of hexagonal plates perched on microcrystalline quartz
Place of Conservation of Type Material:
Type material is deposited in the collections of the Department of Natural History, Royal Ontario Museum, 100 Queens Park, Toronto, Ontario M5S 2C6, Canada, catalogue number M56436
Associated Minerals at Type Locality:
Synonyms of Backite
Common Associates
Associated Minerals Based on Photo Data:
| 2 photos of Backite associated with Flaggite | Pb4Cu2+4Te6+2(SO4)2O11(OH)2(H2O) |
| 2 photos of Backite associated with Fuettererite | Pb3Cu2+6Te6+O6(OH)7Cl5 |
Related Minerals - Strunz-mindat Grouping
| 7.BC. | Adranosite-(Fe) | (NH4)4NaFe3+2(SO4)4Cl(OH)2 |
| 7.BC. | Adranosite | (NH4)4NaAl2(SO4)4Cl(OH)2 |
| 7.BC. | D'Ansite-(Mn) | Na21Mn2+(SO4)10Cl3 |
| 7.BC. | Agaite | Pb3CuTeO5(OH)2(CO3) |
| 7.BC. | D'Ansite-(Fe) | Na21Fe2+(SO4)10Cl3 |
| 7.BC. | Acmonidesite | (NH4,K,Pb)8NaFe2+4(SO4)5Cl8 |
| 7.BC. | Hagstromite | Pb8Cu2+(Te6+O6)2(CO3)Cl4 |
| 7.BC. | Wildcatite | CaFe3+Te6+O5(OH) |
| 7.BC. | Franksousaite | PbCu(Se6+O4)(OH)2 |
| 7.BC. | Zincochenite | Pb4Zn(OH)6(SO4)2 |
| 7.BC. | Viskontite | Pb5Cu2(SO4)3(SeO3)(OH)6 |
| 7.BC.05 | D'Ansite | Na21Mg(SO4)10Cl3 |
| 7.BC.07 | Apatelite | Fe3(SO4)2(OH)5 · 0.5H2O |
| 7.BC.07 | Unnamed (Ba-Fe Vanadate) | Ba, Fe, V, O, H |
| 7.BC.10 | Alunite | KAl3(SO4)2(OH)6 |
| 7.BC.10 | Ammonioalunite | (NH4)Al3(SO4)2(OH)6 |
| 7.BC.10 | Ammoniojarosite | (NH4)Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Argentojarosite | AgFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Beaverite-(Cu) | Pb(Fe3+2Cu)(SO4)2(OH)6 |
| 7.BC.10 | Dorallcharite | TlFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Huangite | Ca0.5Al3(SO4)2(OH)6 |
| 7.BC.10 | Hydroniumjarosite | (H3O)Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Jarosite | KFe3+3(SO4)2(OH)6 |
| 7.BC.10 | Natroalunite-2c | (Na,Ca0.5,K)Al3(SO4)2(OH)6 |
| 7.BC.10 | Natroalunite | NaAl3(SO4)2(OH)6 |
| 7.BC.10 | Natrojarosite | NaFe3(SO4)2(OH)6 |
| 7.BC.10 | Osarizawaite | Pb(Al2Cu2+)(SO4)2(OH)6 |
| 7.BC.10 | Plumbojarosite | Pb0.5Fe3+3(SO4)2(OH)6 |
| 7.BC.10 | Schlossmacherite | (H3O)Al3(SO4)2(OH)6 |
| 7.BC.10 | Walthierite | Ba0.5Al3(SO4)2(OH)6 |
| 7.BC.10 | Beaverite-(Zn) | Pb(Fe3+2Zn)(SO4)2(OH)6 |
| 7.BC.15 | Ye'elimite | Ca4Al6(SO4)O12 |
| 7.BC.20 | Atlasovite | K(BiO)Cu6Fe3+(SO4)5O3Cl |
| 7.BC.20 | Nabokoite | KCu7(SO4)5(Te4+O3)OCl |
| 7.BC.20 | Puninite | Na2Cu3O(SO4)3 |
| 7.BC.25 | Chlorothionite | K2Cu(SO4)Cl2 |
| 7.BC.30 | Euchlorine | KNaCu3(SO4)3O |
| 7.BC.30 | Fedotovite | K2Cu3(SO4)3O |
| 7.BC.35 | Kamchatkite | KCu3(SO4)2OCl |
| 7.BC.40 | Piypite | K4Cu4O2(SO4)4 · (Na,Cu)Cl |
| 7.BC.45 | Klyuchevskite | K3Cu3(Fe3+,Al)(SO4)4O2 |
| 7.BC.45 | Alumoklyuchevskite | K3Cu3(Al,Fe3+)(SO4)4O2 |
| 7.BC.45 | Belousovite | KZn(SO4)Cl |
| 7.BC.47 | Müllerite | Pb2Fe3+(Te6+O6)Cl |
| 7.BC.50 | Caledonite | Pb5Cu2(SO4)3(CO3)(OH)6 |
| 7.BC.50 | Elasmochloite | Na3Cu6BiO4(SO4)5 |
| 7.BC.52 | Eleomelanite | (K2Pb)Cu4O2(SO4)4 |
| 7.BC.55 | Wherryite | Pb7Cu2(SO4)4(SiO4)2(OH)2 |
| 7.BC.55 | Falgarite | K4(VO)3(SO4)5 |
| 7.BC.57 | Krasheninnikovite | KNa2CaMg(SO4)3F |
| 7.BC.60 | Mammothite | Pb6Cu4AlSb5+O2(OH)16Cl4(SO4)2 |
| 7.BC.60 | Wulffite | K3NaCu4O2(SO4)4 |
| 7.BC.60 | Parawulffite | K5Na3Cu8O4(SO4)8 |
| 7.BC.62 | Shuvalovite | K2(Ca2Na)(SO4)3F |
| 7.BC.65 | Linarite | PbCu(SO4)(OH)2 |
| 7.BC.65 | Schmiederite | Pb2Cu2(Se6+O4)(Se4+O3)(OH)4 |
| 7.BC.65 | Munakataite | Pb2Cu2(Se4+O3)(SO4)(OH)4 |
| 7.BC.65 | Therasiaite | (NH4)3KNa2Fe2+Fe3+(SO4)3Cl5 |
| 7.BC.65 | Saccoite | Ca2Mn3+2F(OH)8 · 0.5(SO4) |
| 7.BC.70 | Chenite | Pb4Cu(SO4)2(OH)6 |
| 7.BC.75 | Krivovichevite | Pb3Al(OH)6(SO4)(OH) |
| 7.BC.80 | Anhydrokainite | KMg(SO4)Cl |
Fluorescence of Backite
Does not fluoresce under ultraviolet light.
Other Information
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 Backite
mindat.org URL:
https://www.mindat.org/min-46057.html
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External Links:
References for Backite
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2014) New minerals and nomenclature modifications approved in 2014, CNMNC Newsletter No 19. Mineralogical Magazine, 78 (1) 165-170 doi:10.1180/minmag.2014.078.1.12
Tait, Kimberly T., Dicecco, Veronica, Ball, Neil A., Hawthorne, Frank C., Kampf, Anthony R. (2014) Backite, Pb2Al(TeO6)Cl, a new tellurate mineral from the Grand Central mine, Tombstone Hills, Cochise County, Arizona: description and crystal structure. The Canadian Mineralogist, 52 (6) 935-942 doi:10.3749/canmin.1400047
Localities for Backite
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.
USA (TL) | |
| Williams et al. (2014) +2 other references |
| Marek Chorazewicz (2022) |
| Dr. Robert Housley (2022) |
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Grand Central Mine, Contention-Grand Central Mine group, Tombstone Mining District, Cochise County, Arizona, USA