Bigcreekite
A valid IMA mineral species
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About Bigcreekite
Eckhard D. Stuart at the Esquire No.7
Esquire No. 7 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
Esquire No. 7 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA
Formula:
BaSi2O5 · 4H2O
Colour:
White to colourless
Lustre:
Vitreous, Pearly
Hardness:
2 - 3
Specific Gravity:
2.66
Crystal System:
Orthorhombic
Name:
For the type locality at the Esquire No. 7 claim, Big Creek, Fresno County, California, USA.
This page provides mineralogical data about Bigcreekite.
Unique Identifiers
Mindat ID:
7083
Long-form identifier:
mindat:1:1:7083:2
IMA Classification of Bigcreekite
Classification of Bigcreekite
9.DF.30
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
9 : SILICATES (Germanates)
D : Inosilicates
F : Inosilicates with 2-periodic multiple chains
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 |
|---|---|---|
| Big | 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 Bigcreekite
Vitreous, Pearly
Colour:
White to colourless
Streak:
White
Hardness:
2 - 3 on Mohs scale
Hardness Data:
Measured
Tenacity:
Brittle
Cleavage:
Perfect
{010} and {001}
{010} and {001}
Fracture:
Irregular/Uneven
Density:
2.66 g/cm3 (Measured) 2.76 g/cm3 (Calculated)
Optical Data of Bigcreekite
Type:
Biaxial (+)
RI values:
nα = 1.537 nβ = 1.538 nγ = 1.541
2V:
Measured: 59° , Calculated: 62°
Max. Birefringence:
δ = 0.004
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:
None to Very Low
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 biaxial acute bisectrix (Bxa) interference figure
- the conoscopic view for a grain cut perpendicular to the acute bisectrix, using
this mineral's 2V. The two small white dots mark the melatopes - the points
where the two optic axes emerge - and are shown only when they fall within the
field of view. The coloured bands are isochromatics, and the dark bands are
isogyres.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Rotate the stage: at 0°/90° the isogyres form a cross through the melatopes; at 45° they pull apart into curved hyperbolas. That splitting on rotation - absent in a uniaxial figure - is the standard diagnostic test for telling biaxial minerals from uniaxial ones. If 2V is large, the melatopes may fall outside the field of view, as they often do at the microscope too.
Dispersion:
r < v moderate
Pleochroism:
Non-pleochroic
Chemistry of Bigcreekite
Mindat Formula:
BaSi2O5 · 4H2O
Element Weights:
Elements listed:
Common Impurities:
Ca,Sr,Na
Crystallography of Bigcreekite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Space Group:
Pnma
Cell Parameters:
a = 5.038 Å, b = 9.024 Å, c = 18.321 Å
Ratio:
a:b:c = 0.558 : 1 : 2.03
Unit Cell V:
833 ų
Z:
4
Twinning:
None mentioned
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Show
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Big Balls | Small Balls | Just Balls | Spacefill
Polyhedra Off | Si Polyhedra | All Polyhedra
Remove metal-metal sticks
Display Options
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
Black Background | White Background
Perspective On | Perspective Off
2D | Stereo | Red-Blue | Red-Cyan
View
CIF File Best | x | y | z | a | b | c
CIF File Best | x | y | z | a | b | c
Rotation
Stop | Start
Stop | Start
Labels
Console Off | On | Grey | Yellow
Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0005718 | Bigcreekite | Basciano L C, Groat L A, Roberts A C, Gault R A, Dunning G E, Walstrom R E (2001) Bigcreekite: A new barium silicate mineral species from Fresno County, California The Canadian Mineralogist 39 761-768 |  | 2001 | Fresno County, California, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.068 Å | (100) |
| 4.054 Å | (85) |
| 2.257 Å | (75) |
| 2.706 Å | (60) |
| 2.974 Å | (45) |
| 2.327 Å | (40) |
| 9.19 Å | (30) |
Comments:
Big Creek, California, USA. Data from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] |
Type Occurrence of Bigcreekite
Place of Conservation of Type Material:
M.Y. Williams Museum at the University of British Columbia, Vancouver, British Columbia.
Geological Setting of Type Material:
In fractures in gneissic rocks.
Associated Minerals at Type Locality:
Synonyms of Bigcreekite
Other Language Names for Bigcreekite
Dutch:Bigcreekiet
German:Bigcreekit
Russian:Бигкрикит
Simplified Chinese:水硅钡石
Spanish:Bigcreekita
Traditional Chinese:水矽鋇石
Common Associates
Associations Based on Photo Data:
| 2 photos of Bigcreekite associated with Quartz | SiO2 |
| 1 photo of Bigcreekite associated with Sanbornite | BaSi2O5 |
Related Minerals - Strunz-mindat Grouping
| 9.DF. | Bohseite | Ca4Be3+xAl1-xSi9O25-x(OH)3+x |
| 9.DF.05 | Jimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
| 9.DF.05 | Clinojimthompsonite | (Mg,Fe)5Si6O16(OH)2 |
| 9.DF.05 | Chesterite | (Mg,Fe)17Si20O54(OH)6 |
| 9.DF.15 | Ershovite | Na4K3(Fe,Mn,Ti)2Si8O22(OH)4 · 4H2O |
| 9.DF.15 | Paraershovite | Na3K3Fe3+2Si8O20(OH)4 · 4H2O |
| 9.DF.20 | Tvedalite | (Ca,Mn)4Be3Si6O17(OH)4 · 3H2O |
| 9.DF.25 | Bavenite | Ca4Be2Al2Si9O26(OH)2 |
Fluorescence of Bigcreekite
None
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 Bigcreekite
mindat.org URL:
https://www.mindat.org/min-7083.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
Mineral Dealers:
References for Bigcreekite
Reference List:
Basciano, L. C., Groat, L. A., Roberts, A. C., Gault, R. A., Dunning, G. E., Walstrom, R. E. (2001) Bigcreekite: a new barium silicate mineral species from Fresno County, California. The Canadian Mineralogist, 39 (3) 761-768 doi:10.2113/gscanmin.39.3.761
Localities for Bigcreekite
Showing 3 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.
USA (TL) | |
| Walstrom (n.d.) +2 other references |
| Walstrom (n.d.) |
| Roberts et al. (2001) |
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Esquire No. 7 claim, Big Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA