Sanbornite
A valid IMA mineral species - grandfathered
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About Sanbornite
Formula:
BaSi2O5
Also given as Ba2(Si4O10).
Colour:
Colourless to white
Lustre:
Vitreous, Sub-Vitreous, Pearly
Hardness:
5
Specific Gravity:
3.70
Crystal System:
Orthorhombic
Name:
Named by Austin F. Rogers in honor of George Frank Sanborn (8 July 1881 - 5 August 1945), mineralogist, California Division of Mines, Department of Natural Resources, San Francisco, California, USA.
This page provides mineralogical data about Sanbornite.
Unique Identifiers
Mindat ID:
3518
Long-form identifier:
mindat:1:1:3518:3
IMA Classification of Sanbornite
Approved, 'Grandfathered' (first described prior to 1959)
First published:
1932
Classification of Sanbornite
9.EF.10
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
9 : SILICATES (Germanates)
E : Phyllosilicates
F : Single nets with 6-membered rings, connected by M[4], M[8], etc.
74.3.4.1
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
74 : PHYLLOSILICATES Modulated Layers
3 : Modulated Layers with joined strips
14.7.1
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
14 : Silicates not Containing Aluminum
7 : Silicates of Ba, Sr and Zn
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 |
|---|---|---|
| Sabn | 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 Sanbornite
Vitreous, Sub-Vitreous, Pearly
Transparency:
Translucent
Colour:
Colourless to white
Streak:
White
Hardness:
5 on Mohs scale
Tenacity:
Brittle
Cleavage:
Perfect
{001} perfect, imperfect on {100} and {010}
{001} perfect, imperfect on {100} and {010}
Density:
3.70(2) g/cm3 (Measured) 3.77 g/cm3 (Calculated)
Optical Data of Sanbornite
Type:
Biaxial (-)
RI values:
nα = 1.597(1) nβ = 1.617(2) nγ = 1.625(2)
2V:
Measured: 67° , Calculated: 65°
Max. Birefringence:
δ = 0.028
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:
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 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 weak
Chemistry of Sanbornite
Mindat Formula:
BaSi2O5
Also given as Ba2(Si4O10).
Also given as Ba2(Si4O10).
Element Weights:
Elements listed:
Common Impurities:
Al,Fe,Mg,Ca,Sr,H2O
Crystallography of Sanbornite
Crystal System:
Orthorhombic
Class (H-M):
mmm(2/m2/m2/m) - Dipyramidal
Cell Parameters:
a = 4.629(1) Å, b = 7.688(1) Å, c = 13.523(1) Å
Ratio:
a:b:c = 0.602 : 1 : 1.759
Unit Cell V:
481.25 ų (Calculated from Unit Cell)
Z:
4
Twinning:
Polysynthetic on {100}.
Comment:
Space Group: Pcmn:
Crystal Structure
Load
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
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CIF File Best | x | y | z | a | b | c
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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) |
|---|---|---|---|---|---|---|---|
| 0015374 | Sanbornite | Goreaud M, Choisnet J, Raveau B, Deschanvres A (1974) Sur les silicogermanates Ba (Si2-x Gex) O5 isotypes de la sanbornite _cod_database_code 1001772 Revue de Chimie Minerale 11 207-216 | 1974 | 0 | 293 | ||
| 0000085 | Sanbornite | Douglass R M (1958) The crystal structure of sanbornite, BaSi2O5 American Mineralogist 43 517-536 |  | 1958 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.97 Å | (100) |
| 3.092 Å | (75) |
| 3.342 Å | (70) |
| 2.720 Å | (55) |
| 3.422 Å | (50) |
| 2.130 Å | (40) |
| 6.79 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 36 : Carbonatites, kimberlites, and related igneous rocks | |
| Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
| 50 : Coal and/or oil shale minerals | <0.36 |
| Stage 10b: Anthropogenic minerals | <10 Ka |
| 54 : Coal and other mine fire minerals (see also #51 and #56) |
Type Occurrence of Sanbornite
General Appearance of Type Material:
Anhedral plates.
Place of Conservation of Type Material:
n.d.
Geological Setting of Type Material:
Metamorphosed sediments.
Associated Minerals at Type Locality:
Other Language Names for Sanbornite
Dutch:Sanborniet
German:Sanbornit
Russian:Санборнит
Simplified Chinese:硅钡石
Spanish:Sanbornita
Traditional Chinese:矽鋇石
Common Associates
Associations Based on Photo Data:
| 66 photos of Sanbornite associated with Gillespite | BaFe2+Si4O10 |
| 50 photos of Sanbornite associated with Quartz | SiO2 |
| 23 photos of Sanbornite associated with Titantaramellite | Ba4(Ti,Fe3+,Fe2+,Mg)4(B2Si8O27)O2Clx |
| 19 photos of Sanbornite associated with Pyrrhotite | Fe1-xS |
| 14 photos of Sanbornite associated with Celsian | Ba(Al2Si2O8) |
| 13 photos of Sanbornite associated with Cerchiaraite-(Fe) | Ba4Fe3+4O3(OH)3(Si4O12)[Si2O3(OH)4]Cl |
| 12 photos of Sanbornite associated with Muirite | Ba10(Ca2Mn2+Ti)[Si8O24]O2Cl10 |
| 11 photos of Sanbornite associated with Walstromite | BaCa2(Si3O9) |
| 10 photos of Sanbornite associated with Kampfite | Ba12(Si11Al5)O31(CO3)8Cl5 |
| 9 photos of Sanbornite associated with Pellyite | Ba2CaFe2+2Si6O17 |
Related Minerals - Strunz-mindat Grouping
| 9.EF.05 | Petalite | LiAl(Si4O10) |
| 9.EF.15 | Searlesite | Na(H2BSi2O7) |
| 9.EF.20 | Silinaite | NaLiSi2O5 · 2H2O |
| 9.EF.25 | Kanemite | HNaSi2O5 · 3H2O |
| 9.EF.30 | Yakovenchukite-(Y) | K3NaCaY2[Si12O30] · 4H2O |
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 Sanbornite
mindat.org URL:
https://www.mindat.org/min-3518.html
Please feel free to link to this page.
Please feel free to link to this page.
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Mineral Dealers:
References for Sanbornite
Reference List:
Rogers, Austin F. (1932) Sanbornite, a new barium silicate mineral from Mariposa County, California. American Mineralogist, 17 (5) 161-172
Douglass, Robert M. (1958) The crystal structure of sanbornite, BaSi2O5. American Mineralogist, 43 (5-6) 517-536
Localities for Sanbornite
Showing 29 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.
Argentina | |
| Aristarain (1993) |
Austria | |
| Kolitsch et al. (2025) |
Canada | |
| www.gia.edu (2006) |
| Mitchell et al. (2017) |
| Mitchell et al. (2017) |
| Montgomery et al. (1972) +3 other references |
China | |
| Xue et al. (2021) |
| Xue et al. (2021) | |
Israel | |
| Krzątała et al. (2020) |
| Krzątała et al. (2023) | |
Mexico | |
| |
| Dunning et al. (2018) | |
| Pabst et al. (1984) +2 other references |
North Macedonia | |
| Bermanec et al. (1993) |
| Chukanov et al. (2015) |
Poland | |
| Łukasz Kruszewski preliminary ... |
| Ł. Kruszewski EPMA data (publication in progress) |
Russia | |
| Kazachenko et al. (2024) |
USA | |
| Anonymous (1963) +2 other references |
| Walstrom (n.d.) +2 other references | |
| Bob Walstrom +1 other reference | |
| Walstrom (n.d.) |
| Walstrom (n.d.) +2 other references | |
| Walstrom (n.d.) | |
| Walstrom (n.d.) | |
| Marek Patus +1 other reference | |
| Rogers (1932) +6 other references |
| Pabst (1978) +4 other references |
| Walstrom (n.d.) |
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Esquire No. 1 claim, Rush Creek, Big Creek-Rush Creek Mining District, Fresno County, California, USA