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Perhamite
A valid IMA mineral species
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About Perhamite
Formula:
Ca3Al7.7Si3P4O23.5(OH)14.1 · 8H2O
Colour:
Colourless, white, light brown, yellow, orange
Lustre:
Vitreous, Sub-Vitreous, Pearly
Hardness:
5
Specific Gravity:
2.64
Crystal System:
Trigonal
Member of:
Name:
Named in honor of Frank Croydon Perham (5 March 1934 - January 31, 2023), geologist and pegmatite miner of West Paris, Maine, USA, in honor and recognition of his dedicated labors in the recovery of mineral specimens.
Structurally related to crandallite but not a member of the Plumbogummite Group.
Visually similar to various crandallite-group minerals and iangreyite. See also krásnoite, a mineral closely related to perhamite.
Stands for a precursor for iangreyite, via selective leaching of layer-contained silica followed by layers rejoining via coalescence of the AlO4 tetrahedra from the adjacent layers into trigonal bypiramids of the AlO2(OH)3 composion (Keck et al., 2022).
Visually similar to various crandallite-group minerals and iangreyite. See also krásnoite, a mineral closely related to perhamite.
Stands for a precursor for iangreyite, via selective leaching of layer-contained silica followed by layers rejoining via coalescence of the AlO4 tetrahedra from the adjacent layers into trigonal bypiramids of the AlO2(OH)3 composion (Keck et al., 2022).
Unique Identifiers
Mindat ID:
3160
Long-form identifier:
mindat:1:1:3160:4
IMA Classification of Perhamite
Approved
IMA Formula:
Ca3Al7.7Si3P4O23.5(OH)14.1·8H2O
Approval year:
1975
First published:
1977
Classification of Perhamite
8.DO.20
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
O : With CO3, SO4, SiO4
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
O : With CO3, SO4, SiO4
43.5.10.1
43 : COMPOUND PHOSPHATES, ETC.
5 : Hydrated Compound Phosphates, etc·, Containing Hydroxyl or Halogen
43 : COMPOUND PHOSPHATES, ETC.
5 : Hydrated Compound Phosphates, etc·, Containing Hydroxyl or Halogen
17.6.2
17 : Silicates Containing other Anions
6 : Silicates with phosphate
17 : Silicates Containing other Anions
6 : Silicates with phosphate
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 |
|---|---|---|
| Phm | 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 Perhamite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Perhamite
Vitreous, Sub-Vitreous, Pearly
Transparency:
Transparent, Translucent
Comment:
Vitreous on cleavage
Colour:
Colourless, white, light brown, yellow, orange
Streak:
White
Hardness:
5 on Mohs scale
Tenacity:
Very brittle
Cleavage:
Imperfect/Fair
Imperfect on {0001}
Imperfect on {0001}
Density:
2.64 g/cm3 (Measured) 2.53 g/cm3 (Calculated)
Optical Data of Perhamite
Type:
Uniaxial (+)
RI values:
nω = 1.564(2) nε = 1.577(4)
Max. Birefringence:
δ = 0.013
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:
Moderate (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.
Dispersion:
r > v moderate
Chemistry of Perhamite
Mindat Formula:
Ca3Al7.7Si3P4O23.5(OH)14.1 · 8H2O
Element Weights:
Common Impurities:
Ti,Fe,Mg,Na,F
Crystallography of Perhamite
Crystal System:
Trigonal
Class (H-M):
3m(32/m) - Hexagonal Scalenohedral
Space Group:
P3m1
Cell Parameters:
a = 7.021 Å, c = 20.218 Å
Ratio:
a:c = 1 : 2.88
Unit Cell V:
863.11 ų (Calculated from Unit Cell)
Morphology:
Spherulitic masses of platy crystals, also in rosettes.
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
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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
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Stop | Start
Labels
Console Off | On | Grey | Yellow
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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) |
|---|---|---|---|---|---|---|---|
| 0014576 | Perhamite | Mills S, Mumme G, Grey I, Bordet P (2006) The crystal structure of perhamite Mineralogical Magazine 70 201-209 | 2006 | Emmons mine, Greenwood, Maine | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.71 Å | (40) |
| 6.08 Å | (50) |
| 5.80 Å | (70) |
| 3.51 Å | (50) |
| 3.12 Å | (50) |
| 3.01 Å | (40) |
| 2.88 Å | (100) |
| 1.76 Å | (50) |
Comments:
NOTE: In the calculated pattern, the strongest reflection is at d = 20.2 A. The powder diffraction pattern shows a close resemblance to that of iangreyite.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Perhamite
Co-Type Localities:
General Appearance of Type Material:
Rosettes of pseudo-hexagonal plates; also earthy.
Place of Conservation of Type Material:
The Natural History Museum, London, England number 1976,424.
National Museum of Natural History, Washington, D.C., USA, number 135740, 143393.
National Museum of Natural History, Washington, D.C., USA, number 135740, 143393.
Geological Setting of Type Material:
Originally from late stage mineralization in granite pegmatite. Subsequently found in oxidized zones of ore deposits.
Associated Minerals at Type Locality:
Synonyms of Perhamite
Other Language Names for Perhamite
Relationship of Perhamite to other Species
Member of:
Other Members of Perhamite Group:
| Krásnoite | Ca3Al7.7Si3P4O23.5(OH)12.1F2 · 8H2O | Trig. 3m(32/m) : P3m1 |
Chemically related to group(s):
| Plumbogummite Group | A subgroup of the Alunite Supergroup. |
Common Associates
Associations Based on Photo Data:
| 10 photos of Perhamite associated with Albite | Na(AlSi3O8) |
| 6 photos of Perhamite associated with Lipscombite | Fe2+Fe3+2(PO4)2(OH)2 |
| 6 photos of Perhamite associated with Turquoise | CuAl6(PO4)4(OH)8 · 4H2O |
| 4 photos of Perhamite associated with Quartz | SiO2 |
| 3 photos of Perhamite associated with Wavellite | Al3(PO4)2(OH)3 · 5H2O |
| 2 photos of Perhamite associated with Hydroxylherderite | CaBe(PO4)(OH) |
| 2 photos of Perhamite associated with Wardite | NaAl3(PO4)2(OH)4 · 2H2O |
| 2 photos of Perhamite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 1 photo of Perhamite associated with Kidwellite | NaFe3+9+x(PO4)6(OH)11 · 3H2O, x = 0.33 |
| 1 photo of Perhamite associated with Gorceixite | BaAl3(PO4)(PO3OH)(OH)6 |
Related Minerals - Strunz-mindat Grouping
| 8.DO. | Whiterockite | CaMgMn3+3O2(PO4)2(CO3)F · 5H2O |
| 8.DO.05 | Girvasite | NaCa2Mg3(PO4)3(CO3)(H2O)6 |
| 8.DO.10 | Voggite | Na2Zr(PO4)(CO3)(OH) · 2H2O |
| 8.DO.15 | Peisleyite | Na2Al9[(P,S)O4]8(OH)6 · 28H2O |
| 8.DO.20 | Krásnoite | Ca3Al7.7Si3P4O23.5(OH)12.1F2 · 8H2O |
| 8.DO.25 | Saryarkite-(Y) | Ca(Y,Th)Al5(SiO4)2(PO4,SO4)2(OH)7 · 6H2O |
| 8.DO.30 | Micheelsenite | (Ca2Y)Al(PO3OH)(CO3)(OH)6 · 12H2O |
| 8.DO.40 | Parwanite | (Na,K)(Mg,Ca)4Al8(PO4)8(CO3)(OH)7 · 30H2O |
| 8.DO.45 | Skorpionite | Ca3Zn2(PO4)2(CO3)(OH)2 · H2O |
| 8.DO.50 | Jörgkellerite | (Na,◻)3Mn3+3(PO4)2(CO3)(O,OH)2 · 5H2O |
| 8.DO.55 | Juansilvaite | Na5Al3[AsO3(OH)]4[AsO2(OH)2]2(SO4)2 · 4H2O |
| 8.DO.60 | Vanderheydenite | Zn6(PO4)2(SO4)(OH)4 · 7H2O |
Fluorescence of Perhamite
Not fluorescent
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 Perhamite
mindat.org URL:
https://www.mindat.org/min-3160.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 Perhamite
Reference List:
Dunn, Pete J., Appleman, Daniel E. (1977) Perhamite, a new calcium aluminum silico-phosphate mineral, and a re-examination of viséite. Mineralogical Magazine, 41 (320) 437-442 doi:10.1180/minmag.1977.041.320.03
Fleischer, Michael; Pabst, Adolf, White, John Sampson (1978) New mineral names. American Mineralogist, 63 (7-8). 793-796
Locock, A. J., Ercit, T. S., Kjellman, J., Piilonen, P. C. (2006) New mineral names. American Mineralogist, 91 (11) 1945-1954 doi:10.2138/am.2006.477
Mills, S., Mumme, G., Grey, I., Bordet, P. (2006) The crystal structure of perhamite. Mineralogical Magazine, 70 (2) 201-209 doi:10.1180/0026461067020324
Ercit, T. S., Piilonen, P. C., Rowe, R. (2007) NEW MINERAL NAMES. American Mineralogist, 92 (8) 1539-1542 doi:10.2138/am.2007.499
Keck, Erich, Grey, Ian E., MacRae, Colin M., Boer, Stephanie, Hochleitner, Rupert, Rewitzer, Christian, Mumme, William G., Glenn, A. Matt, Davidson, Cameron (2022) New secondary phosphate mineral occurrences and their crystal chemistry, at the Hagendorf Süd pegmatite, Bavaria. European Journal of Mineralogy, 34 (5) 439-450 doi:10.5194/ejm-34-439-2022
Localities for Perhamite
Showing 31 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.
Australia | |
| Mills (2003) |
| Francis et al. (self published) +2 other references | |
| Mills (2003) |
| Francis et al. (2012) |
Austria | |
| Niedermayr et al. (2005) |
| Walter et al. (2026) |
| H.Wippel |
Bolivia | |
| Anatoly Kasatkin analysis on Richie ... +1 other reference |
Czech Republic | |
| Breiter K. |
| Sejkora et al. (2011) |
France | |
| Kolitsch et al. (2009) |
Germany | |
| Keck et al. (2022) |
| Wittern (2001) |
Norway | |
| Kristiansen (2014) |
Russia | |
| ... |
| Belogub et al. (2026) |
Spain | |
| Rosell-Riba et al. (2022) |
| Bosch +6 other references | |
USA | |
| Roberts et al. (2003) |
| King (2000) |
| Rocks and Minerals (1980) +4 other references |
| Found Oct 2021 and optically studied. ... | |
| Dunn et al. (1977) +2 other references |
| Dunn et al. (1977) |
| www.mindat.org (2004) +1 other reference |
| King (2000) +1 other reference |
| E.L. Clopton collection |
| Dr. William S. Wise presentation to ... |
| Tom Mortimer collection (EDS- and PXRD-analysed) |
| Thomas Loomis Collection |
| Joe Marty et al. (1999) |
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Golden Reward Mine, Ruby Basin Mining District, Lawrence County, South Dakota, USA