Cerchiaraite-(Al)
A valid IMA mineral species
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About Cerchiaraite-(Al)
Formula:
Ba4Al4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl
Colour:
Blue to bluish-green
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
3.69
Crystal System:
Tetragonal
Member of:
Name:
in allusion to relation with "cerchiaraite" (now cerchiaraite-(Mn))
Co-Type Localities:
ⓘ Esquire No. 7 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 8 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 8 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
Isostructural with:
The Al analogue of cerchiaraite-(Mn) (ex-cerchiaraite) and cerchiaraite-(Fe). Chemically related to meierite.
The structure details (1) corner-sharing silicate tetrahedra, forming 4-membered rings; (2) the rings share corners with an edge-sharing chain of AlO6 octahedra || c; (3) the rings alternate with Cl sites alternates along c; (4) large channels in the framework host Ba around their peripheries, statistically distributed Si2O3(OH)4 dimers, and Cl atoms.
The structure details (1) corner-sharing silicate tetrahedra, forming 4-membered rings; (2) the rings share corners with an edge-sharing chain of AlO6 octahedra || c; (3) the rings alternate with Cl sites alternates along c; (4) large channels in the framework host Ba around their peripheries, statistically distributed Si2O3(OH)4 dimers, and Cl atoms.
Unique Identifiers
Mindat ID:
42782
Long-form identifier:
mindat:1:1:42782:3
Similar Names
| Cerchiaraite-(Fe) | A valid IMA mineral species | Ba4Fe43+O3(OH)3(Si4O12)[Si2O3(OH)4]Cl |
| Cerchiaraite-(Mn) | A valid IMA mineral species | Ba4Mn43+(Si4O12)O2(OH)4Cl2[Si2O3(OH)4] |
| Cherchiaraite | A synonym of Cerchiaraite Group |
IMA Classification of Cerchiaraite-(Al)
Classification of Cerchiaraite-(Al)
9.CF.25
9 : SILICATES (Germanates)
C : Cyclosilicates
F : [Si4O12]8- 4-membered single rings, with insular complex anions
9 : SILICATES (Germanates)
C : Cyclosilicates
F : [Si4O12]8- 4-membered single rings, with insular complex anions
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 |
|---|---|---|
| Ccr-Al | 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 Cerchiaraite-(Al)
Vitreous
Transparency:
Transparent
Colour:
Blue to bluish-green
Streak:
Pale blue-green
Hardness:
4½ on Mohs scale
Comment:
ca. 4.5
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Irregular/Uneven
Density:
3.69(3) g/cm3 (Measured) 3.643 g/cm3 (Calculated)
Optical Data of Cerchiaraite-(Al)
Type:
Uniaxial (-)
RI values:
nω = 1.695(2) nε = 1.677(2)
Max. Birefringence:
δ = 0.018
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:
Very High (positive)
Relative to Canada balsam mounting medium (n ≈ 1.537).
Relative to Canada balsam mounting medium (n ≈ 1.537).
This shows the grain boundary and Becke line effect under plane-polarised
light, based on the contrast between this mineral's average refractive
index and the mounting medium. It does not take into account mineral
colouration.
In focus
Interference Figure:
This shows the idealized uniaxial interference figure - the conoscopic
(convergent-light, Bertrand-lens-in) view, for a grain cut with the optic axis
centred and vertical. The coloured rings are isochromatics, computed with the
same physics as the Michel-Lévy bar above; the dark cross is the isogyre.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
For a genuinely uniaxial mineral viewed this way, that cross stays perfectly stationary if you rotate the stage - unlike a biaxial mineral, where it splits apart on rotation. That invariance is itself the standard diagnostic test for telling uniaxial and biaxial minerals apart at the microscope.
Pleochroism:
Strong
Comments:
colorless (O), blue (E), O < E
Chemistry of Cerchiaraite-(Al)
Mindat Formula:
Ba4Al4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl
Element Weights:
Common Impurities:
Fe(III),Mg,Fe(II),(Mn(II))
Crystallography of Cerchiaraite-(Al)
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
I4/mmm
Cell Parameters:
a = 14.317(4) Å, c = 6.0037(18) Å
Ratio:
a:c = 1 : 0.419
Unit Cell V:
1230.6 ų
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.15 Å | (39) |
| 4.407 Å | (39) |
| 3.316 Å | (74) |
| 3.009 Å | (100) |
| 2.580 Å | (93) |
| 2.029 Å | (43) |
| 1.880 Å | (68) |
| 1.403 Å | (54) |
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) |
Geological Setting:
Esquire #7 and #8 claims
Type Occurrence of Cerchiaraite-(Al)
Co-Type Localities:
ⓘ Esquire No. 7 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 8 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 8 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
ⓘ Esquire No. 1 claim, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
General Appearance of Type Material:
subparallel aggregates of irregular prisms, generally less than 1 mm across
Place of Conservation of Type Material:
Natural History Museum of Los Angeles County, Los Angeles, California, USA, catalogue numbers 63519, 63517 and 63518
Geological Setting of Type Material:
quartz-sanbomite vein assemblages resulting fromfluid interaction along the margin of the vein; associated minerals concert Esquire # 1 claim
Associated Minerals at Type Locality:
Synonyms of Cerchiaraite-(Al)
Other Language Names for Cerchiaraite-(Al)
Dutch:Cerchiaraiet-(Al)
German:Cerchiarait-(Al)
Relationship of Cerchiaraite-(Al) to other Species
Member of:
Other Members of Cerchiaraite Group:
| Cerchiaraite-(Fe) | Ba4Fe3+4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl | Tet. 4/mmm(4/m2/m2/m) : I4/mmm |
| Cerchiaraite-(Mn) | Ba4Mn3+4(Si4O12)O2(OH)4Cl2[Si2O3(OH)4] | Tet. 4/mmm(4/m2/m2/m) : I4/mmm |
Common Associates
Associations Based on Photo Data:
| 1 photo of Cerchiaraite-(Al) associated with Sanbornite | BaSi2O5 |
| 1 photo of Cerchiaraite-(Al) associated with Titantaramellite | Ba4(Ti,Fe3+,Fe2+,Mg)4(B2Si8O27)O2Clx |
| 1 photo of Cerchiaraite-(Al) associated with Quartz | SiO2 |
Related Minerals - Strunz-mindat Grouping
| 9.CF. | Bobmeyerite | Pb4(Al3Cu)(Si4O12)(S0.5Si0.5O4)(OH)7Cl(H2O)3 |
| 9.CF.05 | Ashburtonite | Pb4Cu4(Si4O12)(HCO3)4(OH)3Cl · H2O |
| 9.CF.10 | Kainosite-(Y) | Ca2Y2(SiO3)4(CO3) · H2O |
| 9.CF.15 | Clinophosinaite | Na12(Ca,Sr)4(Si4O12)(PO4)4 |
| 9.CF.15 | Phosinaite-(Ce) | Na13Ca2(Ce,La,Th,Nd,Pr)(Si4O12)(PO4)4 |
| 9.CF.20 | Strakhovite | NaBa3Mn2+2Mn3+2Si6O19(OH)3 |
| 9.CF.25 | Cerchiaraite-(Fe) | Ba4Fe3+4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl |
| 9.CF.25 | Cerchiaraite-(Mn) | Ba4Mn3+4(Si4O12)O2(OH)4Cl2[Si2O3(OH)4] |
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 Cerchiaraite-(Al)
mindat.org URL:
https://www.mindat.org/min-42782.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Cerchiaraite-(Al)
Reference List:
Williams, P. A., Hatert, F., Pasero, M., Mills, S. J. (2012) New minerals and nomenclature modifications approved in 2012. CNMNC Newsletter No 13. Mineralogical Magazine, 76 (3) 807-817 doi:10.1180/minmag.2012.076.3.26
Localities for Cerchiaraite-(Al)
Showing 6 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.
Canada | |
| McNeil et al. (2013) +1 other reference |
Sweden | |
| Cámara et al. (2021) |
USA (TL) | |
| Williams et al. (2012) +1 other reference |
| Williams et al. (2012) +2 other references |
| Walstrom (n.d.) +3 other references |
| Walstrom (n.d.) |
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Snow Cap Mine, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA