Samfowlerite
A valid IMA mineral species
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About Samfowlerite
Dr. Samuel Fowler
Formula:
Ca28Mn6Zn4(Be,Zn)4Be12[(OH)3(SiO4)3(Si2O7)2]4
Colour:
Colourless
Lustre:
Vitreous, Sub-Vitreous, Resinous
Hardness:
2½ - 3
Specific Gravity:
3.28
Crystal System:
Monoclinic
Name:
Named in 1994 by Roland C. Rouse, Donald Ralph Peacor, Pete J. Dunn, Shu-Chun Su, Peter H. Chi, and Herb Yeates in honor of Dr. Samuel Fowler [October 30, 1779 Newburgh, New York, USA - February 20, 1844 Franklin, New Jersey, USA], "the pre-eminent figure in the history of the Franklin mining district. Dr. Fowler, a physician, scientist, industrialist, and entrepreneur, was instrumental in bringing most of the great American naturalists and scientists of his time to Franklin and encouraging mineralogists in Europe and elsewhere to study the zinc deposits at Franklin" and a US Congressman from New Jersey, 1833-1837. He enlisted the aid of all scientists he could interest in the deposits of Franklin and Sterling Hill, NJ. In 1810, he purchased Mine Hill, with a partner, in Franklin, site of the Franklin orebody. In 1818 and 1824, he acquired the Sterling Mine from the Ogden family.
Type Locality:
Found as minute acute wedge-like colourless crystals. Due to the common size range (under 500 microns), the mineral is difficult to find. Currently only recorded from the Franklin mine (2024).
Unique Identifiers
Mindat ID:
3513
Long-form identifier:
mindat:1:1:3513:8
IMA Classification of Samfowlerite
Classification of Samfowlerite
9.BF.10
9 : SILICATES (Germanates)
B : Sorosilicates
F : Sorosilicates with mixed SiO4 and Si2O7 groups; cations in tetrahedral [4] and greater coordination
9 : SILICATES (Germanates)
B : Sorosilicates
F : Sorosilicates with mixed SiO4 and Si2O7 groups; cations in tetrahedral [4] and greater coordination
58.2.7.1
58 : SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
2 : Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
58 : SOROSILICATES Insular, Mixed, Single, and Larger Tetrahedral Groups
2 : Insular, Mixed, Single, and Larger Tetrahedral Groups with cations in [6] and higher coordination; single and double groups (n = 1, 2)
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 |
|---|---|---|
| Sfw | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Samfowlerite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Samfowlerite
Vitreous, Sub-Vitreous, Resinous
Transparency:
Transparent
Colour:
Colourless
Streak:
White
Hardness:
2½ - 3 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Density:
3.28 g/cm3 (Measured) 3.30 g/cm3 (Calculated)
Optical Data of Samfowlerite
Type:
Biaxial (-)
RI values:
nα = 1.674 nβ = 1.680 nγ = 1.681
2V:
Measured: 29° , Calculated: 44°
Birefringence:
0.007
Max. Birefringence:
δ = 0.007
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:
relatively strong
Optical Extinction:
Y = b; X ∧ a = 44°; Z ∧ c = 29°.
Pleochroism:
Non-pleochroic
Chemistry of Samfowlerite
Mindat Formula:
Ca28Mn6Zn4(Be,Zn)4Be12[(OH)3(SiO4)3(Si2O7)2]4
Element Weights:
Common Impurities:
Mg,H2O
Crystallography of Samfowlerite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 9.068 Å, b = 17.992 Å, c = 14.586 Å
β = 104.86°
β = 104.86°
Ratio:
a:b:c = 0.504 : 1 : 0.811
Unit Cell V:
2,300.14 ų (Calculated from Unit Cell)
Z:
2
Crystal Structure
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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) |
|---|---|---|---|---|---|---|---|
| 0005361 | Samfowlerite | Rouse R C, Peacor D R, Dunn P J, Su S-C, Chi P H, Yeates H (1994) Samfowlerite, a new Ca Mn Zn beryllosilicate mineral from Franklin, New Jersey: Its characterization and crystal structure The Canadian Mineralogist 32 43-53 |  | 1994 | Franklin, New Jersey, USA | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 7.735 Å | (2) |
| 4.923 Å | (5) |
| 4.515 Å | (2) |
| 4.228 Å | (5) |
| 3.827 Å | (2) |
| 3.570 Å | (10b) |
| 3.336 Å | (2) |
| 3.239 Å | (2) |
| 3.054 Å | (2) |
| 2.863 Å | (100) |
| 2.771 Å | (40) |
| 2.653 Å | (50) |
| 2.582 Å | (10) |
| 2.492 Å | (5) |
| 2.459 Å | (10) |
| 2.388 Å | (50) |
| 2.329 Å | (20) |
| 2.272 Å | (30) |
| 2.184 Å | (2) |
| 2.132 Å | (2) |
| 2.064 Å | (2) |
| 2.036 Å | (2) |
| 1.959 Å | (2) |
| 1.860 Å | (20) |
| 1.832 Å | (30) |
| 1.803 Å | (20) |
| 1.744 Å | (5) |
| 1.721 Å | (5) |
| 1.689 Å | (20) |
| 1.613 Å | (5) |
| 1.526 Å | (10) |
| 1.504 Å | (2) |
| 1.458 Å | (5) |
| 1.432 Å | (5) |
| 1.407 Å | (2) |
| 1.384 Å | (2) |
| 1.303 Å | (5) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| High-? alteration and/or metamorphism | |
| 32 : Ba/Mn/Pb/Zn deposits, including metamorphic deposits |
Type Occurrence of Samfowlerite
General Appearance of Type Material:
Minute asymmetrical appearing colorless crystals (crystal clusters up to 500 microns known with individual crystals about 50 microns); in cavities on or next to colorless cahnite crystals, but only with orange-pink to light green zoned andradite.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, M04254.
Geological Setting of Type Material:
Marble hosted zinc silicate and zinc oxide bearing ore body.
Associated Minerals at Type Locality:
Synonyms of Samfowlerite
Other Language Names for Samfowlerite
Common Associates
Associations Based on Photo Data:
| 6 photos of Samfowlerite associated with Cahnite | Ca2[B(OH)4](AsO4) |
| 6 photos of Samfowlerite associated with Leucophoenicite | Mn2+7(SiO4)3(OH)2 |
| 6 photos of Samfowlerite associated with Clinochlore | Mg5Al(AlSi3O10)(OH)8 |
| 6 photos of Samfowlerite associated with Willemite | Zn2SiO4 |
| 5 photos of Samfowlerite associated with Baryte | BaSO4 |
| 4 photos of Samfowlerite associated with Grossular | Ca3Al2(SiO4)3 |
| 3 photos of Samfowlerite associated with Andradite | Ca3Fe3+2(SiO4)3 |
| 3 photos of Samfowlerite associated with Franklinite | Zn2+Fe3+2O4 |
Related Minerals - Strunz-mindat Grouping
| 9.BF.05 | Harstigite | Ca6(Mn,Mg)Be4Si6(O,OH)24 |
| 9.BF.15 | Davreuxite | MnAl6Si4O17(OH)2 |
| 9.BF.20 | Queitite | Pb4Zn2(SO4)(SiO4)(Si2O7) |
Fluorescence of Samfowlerite
Fluoresceces weakly under both SW and LW ultraviolet, but the minute size of the crystals renders the response almost unobservable, even when viewed with a microscope at 30X.
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 Samfowlerite
mindat.org URL:
https://www.mindat.org/min-3513.html
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Please feel free to link to this page.
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References for Samfowlerite
Localities for Samfowlerite
Showing 2 localities.
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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.
Romania | |
| HÎRTOPANU et al. (2025) |
USA (TL) | |
| Rouse +6 other references |
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Franklin Mine, Franklin, Sussex County, New Jersey, USA