Stringhamite
A valid IMA mineral species
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About Stringhamite
Bronson F. Stringham
Formula:
CaCu(SiO4) · H2O
Colour:
Azure blue
Lustre:
Vitreous
Specific Gravity:
3.16 - 3.18
Crystal System:
Monoclinic
Name:
Named in honour of Bronson Ferrin Stringham (28 July 1907, Salt Lake City, Utah, USA - 30 May 1968, Salt Lake City, Utah, USA) professor and chair of department of mineralogy, University of Utah, USA. He made important contributions to the geology of Utah and described the mineral tinticite.
This page provides mineralogical data about Stringhamite.
Unique Identifiers
Mindat ID:
3802
Long-form identifier:
mindat:1:1:3802:3
IMA Classification of Stringhamite
Approved
IMA Formula:
CaCu2+SiO4·H2O
Approval year:
1974
First published:
1976
Classification of Stringhamite
9.AE.35
9 : SILICATES (Germanates)
A : Nesosilicates
E : Nesosilicates with additional anions (O,OH,F,H2O); cations in tetrahedral [4] coordination
9 : SILICATES (Germanates)
A : Nesosilicates
E : Nesosilicates with additional anions (O,OH,F,H2O); cations in tetrahedral [4] coordination
78.1.9.1
78 : Unclassified Silicates
1 : Miscellaneous
78 : Unclassified Silicates
1 : Miscellaneous
14.2.10
14 : Silicates not Containing Aluminum
2 : Silicates of Cu
14 : Silicates not Containing Aluminum
2 : Silicates of Cu
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 |
|---|---|---|
| Sgh | 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 Stringhamite
Vitreous
Transparency:
Transparent, Translucent
Colour:
Azure blue
Density:
3.16 - 3.18 g/cm3 (Measured) 3.67 g/cm3 (Calculated)
Optical Data of Stringhamite
Type:
Biaxial (+)
RI values:
nα = 1.709 nβ = 1.717 nγ = 1.729
2V:
Measured: 80° , Calculated: 80°
Max. Birefringence:
δ = 0.020
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 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
Pleochroism:
Visible
Comments:
alpha - light grey blue
beta - light blue
gamma - dark blue
beta - light blue
gamma - dark blue
Comments:
X = b, Y∧c = 2.5°
Chemistry of Stringhamite
Mindat Formula:
CaCu(SiO4) · H2O
Element Weights:
Common Impurities:
Al,Fe,Mg
Crystallography of Stringhamite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 5.030(2) Å, b = 16.135(3) Å, c = 5.343(1) Å
β = 102.96(1)°
β = 102.96(1)°
Ratio:
a:b:c = 0.312 : 1 : 0.331
Unit Cell V:
422.59 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystal habit is strongly monoclinic with (011) and (101) being the dominate
forms, with minor (010) and (111).
forms, with minor (010) and (111).
Twinning:
All crystals are multiple-twinned
Crystallographic forms of Stringhamite
Crystal Atlas:
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Stringhamite - {101}, {011}, modified
3d models and HTML5 code kindly provided by
www.smorf.nl.
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Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0015701 | Stringhamite | Hawthorne F C (1985) The crystal structure of stringhamite Tschermaks Mineralogische und Petrographische Mitteilungen 34 15-24 | 1985 | Christmas mine, Pinal County, Arizona, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 2.768 Å | (100) |
| 2.523 Å | (40) |
| 3.236 Å | (39) |
| 8.049 Å | (35) |
| 3.928 Å | (34) |
| 1.614 Å | (23) |
| 4.884 Å | (21) |
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 Stringhamite
General Appearance of Type Material:
Blue crystals to 0.1 mm occuring with crystalline thaumasite on fracture surfaces in diopside-magnetite skarn. Also small radial aggregates of minute crystals occurring with bornite and chalcopyrite disseminated in granular diopside.
Place of Conservation of Type Material:
1) National Museum of Natural History, Washington, D.C., USA, 128031.
2) The Natural History Museum, London, England, 1976,421.
2) The Natural History Museum, London, England, 1976,421.
Geological Setting of Type Material:
In fractures near a contact between quartz monzonite and limestone. Thought to have formed by reaction of copper bearing solutions with diopside.
Associated Minerals at Type Locality:
Synonyms of Stringhamite
Other Language Names for Stringhamite
Common Associates
Associations Based on Photo Data:
| 23 photos of Stringhamite associated with Xonotlite | Ca6(Si6O17)(OH)2 |
| 19 photos of Stringhamite associated with Whelanite | Cu2+2Ca6[Si6O17(OH)](CO3)(OH)3 · 2H2O |
| 13 photos of Stringhamite associated with Tobermorite | Ca5Si6O17 · 5H2O |
| 9 photos of Stringhamite associated with Wayneburnhamite | Pb9Ca6(Si2O7)3(SiO4)3 |
| 9 photos of Stringhamite associated with Gehlenite | Ca2Al[AlSiO7] |
| 9 photos of Stringhamite associated with Calcite | CaCO3 |
| 9 photos of Stringhamite associated with 'Limonite' | |
| 9 photos of Stringhamite associated with Diopside | CaMgSi2O6 |
| 8 photos of Stringhamite associated with Kinoite | Ca2Cu2(H2O)2[Si3O10] |
| 6 photos of Stringhamite associated with Fluorapophyllite-(K) | KCa4(Si8O20)(F,OH) · 8H2O |
Related Minerals - Strunz-mindat Grouping
| 9.AE.05 | Beryllite | Be3(SiO4)(OH)2 · H2O |
| 9.AE.10 | Euclase | BeAl(SiO4)(OH) |
| 9.AE.15 | Sverigeite | NaMnMgSnBe2(SiO4)3(OH) |
| 9.AE.20 | Hodgkinsonite | Mn2+Zn2(SiO4)(OH)2 |
| 9.AE.25 | Gerstmannite | MnMgZn(SiO4)(OH)2 |
| 9.AE.30 | Clinohedrite | CaZn(SiO4) · H2O |
| 9.AE.40 | Katoptrite | (Mn2+,Mg)13(Al,Fe3+)4Sb5+2(SiO4)2O20 |
| 9.AE.45 | Yeatmanite | Zn6Mn2+9Sb5+2(SiO4)4O12 |
| 9.AE.50 | Sphaerobertrandite | Be3(SiO4)(OH)2 |
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 Stringhamite
mindat.org URL:
https://www.mindat.org/min-3802.html
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References for Stringhamite
Reference List:
Hindman, James R. (1976) Stringhamite, a new hydrous copper calcium silicate from Utah. American Mineralogist, 61 (3-4) 189-192
Hawthorne, F. C. (1985) The crystal structure of stringhamite. TMPM Tschermaks Mineralogische und Petrographische Mitteilungen, 34 (1). 15-24 doi:10.1007/bf01082454
Localities for Stringhamite
Showing 10 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.
Chile | |
| Am.Min. 61:189 |
| Bob Jenkins & M. Dini collections |
China | |
| Ottens (2008) |
Japan | |
| Nishimura et al (2001) |
USA | |
| Handbook of Mineralolgy Vol. II Silica |
| Anthony et al. (1995) | |
| Anthony et al. (1995) |
| Kampf et al. (2012) |
| Hindman (1976) +2 other references |
| Kampf et al. (2012) |
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Christmas Mine, Christmas, Banner Mining District, Gila County, Arizona, USA