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Hurlbutite
A valid IMA mineral species - grandfathered
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About Hurlbutite
Dr. Cornelius S. Hurlbut, jr.
Formula:
CaBe2(PO4)2
Colour:
Greenish white, yellow or colourless
Lustre:
Vitreous, Greasy
Hardness:
6
Specific Gravity:
2.877
Crystal System:
Monoclinic
Name:
Named in 1951 by Mary Emma Mrose in honor of Prof. Cornelius Searle Hurlbut, Jr. [June 30, 1906 Massachusetts, USA – September 1, 2005 Lexington, Massachusetts, USA], American mineralogist, professor of mineralogy at Harvard University, Cambridge, Massachusetts, USA.
Ca analogue of strontiohurlbutite. Has a paracelsian-type structure and may thus be alternatively grouped in a "paracelsian group", alongside with paracelsian, slawsonite, danburite, maleevite, pekovite.
Compare minjiangite which is not a true (structural-chemical) but just chemical (Ba) analogue.
Visit gemdat.org for gemological information about Hurlbutite.
Compare minjiangite which is not a true (structural-chemical) but just chemical (Ba) analogue.
Visit gemdat.org for gemological information about Hurlbutite.Unique Identifiers
Mindat ID:
1953
Long-form identifier:
mindat:1:1:1953:4
Similar Names
| Hurlbutite (of Gagarin and Cuomo) | A synonym of 'Wurtzite-4H' |
IMA Classification of Hurlbutite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
CaBe2P2O8
First published:
1952
Type description reference:
Classification of Hurlbutite
8.AA.15
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
A : With small cations (some also with larger ones)
8 : PHOSPHATES, ARSENATES, VANADATES
A : Phosphates, etc. without additional anions, without H2O
A : With small cations (some also with larger ones)
Dana 7th ed.:
38.3.6.1
38.3.6.1
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
3 : (AB)3(XO4)2
38 : ANHYDROUS NORMAL PHOSPHATES, ARSENATES, AND VANADATES
3 : (AB)3(XO4)2
19.3.3
19 : Phosphates
3 : Phosphates of Be and Mg
19 : Phosphates
3 : Phosphates of Be and Mg
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference for Standard |
|---|---|---|
| Hrb | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Hrb | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Physical Properties of Hurlbutite
Vitreous, Greasy
Transparency:
Transparent
Colour:
Greenish white, yellow or colourless
Streak:
White
Hardness:
6 on Mohs scale
Tenacity:
Brittle
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
2.877(5) g/cm3 (Measured) 2.90 g/cm3 (Calculated)
Optical Data of Hurlbutite
Type:
Biaxial (-)
RI values:
nα = 1.595(3) nβ = 1.601(3) nγ = 1.604(3)
2V:
Measured: 70° , Calculated: 70°
Max. Birefringence:
δ = 0.009
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 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.
Optical Extinction:
X = b; Y = c; Z = a.
Chemistry of Hurlbutite
Mindat Formula:
CaBe2(PO4)2
Element Weights:
Elements listed:
Crystallography of Hurlbutite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/c
Setting:
P21/a
Cell Parameters:
a = 8.299(1) Å, b = 8.782(2) Å, c = 7.798(3) Å
β = 90.5°
β = 90.5°
Ratio:
a:b:c = 0.945 : 1 : 0.888
Unit Cell V:
568.31 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Stout prismatic crystals, spheres with a radial fibrous structure.
In the type material, forms c{001} and m{111} are dominant and are truncated by d{201} and b{010}. On one crystal the form e{101} occurred as a very small face.
In the type material, forms c{001} and m{111} are dominant and are truncated by d{201} and b{010}. On one crystal the form e{101} occurred as a very small face.
Crystal Structure
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Unit Cell | Unit Cell Packed
2x2x2 | 3x3x3 | 4x4x4
Unit Cell | Unit Cell Packed
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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) |
|---|---|---|---|---|---|---|---|
| 0000431 | Hurlbutite | Lindbloom J T, Gibbs G V, Ribbe P H (1974) The crystal structure of hurlbutite: A comparison with danburite and anorthite American Mineralogist 59 1267-1271 |  | 1974 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.67 Å | (100) |
| 3.03 Å | (90) |
| 2.78 Å | (90) |
| 2.21 Å | (90) |
| 3.50 Å | (70) |
| 2.50 Å | (70) |
| 3.28 Å | (60) |
Comments:
Chandlers Mill Quarry, New Hampshire, USA. Data are from the type description.
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4a: Earth’s earliest continental crust | >4.4-3.0 |
| 19 : Granitic intrusive rocks | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Hurlbutite
General Appearance of Type Material:
Stout prismatic crystals to 25 mm.
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA, 103923, 104958, 104602, 134548.
Geological Setting of Type Material:
Complex granite pegmatite; observed as an alteration product of beryl.
Associated Minerals at Type Locality:
Synonyms of Hurlbutite
Other Language Names for Hurlbutite
Dutch:Hurlbutiet
German:Hurlbutit
Cherlbutit
Cherlbutit
Russian:Херлбатит
Simplified Chinese:磷钙铍石
Spanish:Cherlbutita
Hurlbutita
Hurlbutita
Common Associates
Associations Based on Photo Data:
| 12 photos of Hurlbutite associated with Tiptopite | K2(Na,Ca)2Li3Be6(PO4)6(OH)2 · H2O |
| 12 photos of Hurlbutite associated with Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O |
| 11 photos of Hurlbutite associated with Väyrynenite | BeMn2+(PO4)(OH) |
| 10 photos of Hurlbutite associated with Hydroxylherderite | CaBe(PO4)(OH) |
| 9 photos of Hurlbutite associated with Quartz | SiO2 |
| 7 photos of Hurlbutite associated with Englishite | K3Na2Ca10Al15(PO4)21(OH)7 · 26H2O |
| 7 photos of Hurlbutite associated with Montgomeryite | Ca4MgAl4(PO4)6(OH)4 · 12H2O |
| 7 photos of Hurlbutite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 6 photos of Hurlbutite associated with Beryllonite | NaBePO4 |
| 3 photos of Hurlbutite associated with Beryl | Be3Al2(Si6O18) |
Related Minerals - Strunz-mindat Grouping
| 8.AA.05 | Alarsite | AlAsO4 |
| 8.AA.05 | Berlinite | AlPO4 |
| 8.AA.10 | Beryllonite | NaBePO4 |
| 8.AA.20 | Lithiophosphate | Li3PO4 |
| 8.AA.25 | Nalipoite | NaLi2PO4 |
| 8.AA.30 | Olympite | Na5Li(PO4)2 |
Fluorescence of Hurlbutite
Not fluorescent.
Other Information
Thermal Behaviour:
Difficult to fuse.
Notes:
Very slowly soluble in acids.
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 Hurlbutite
mindat.org URL:
https://www.mindat.org/min-1953.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 Hurlbutite
Reference List:
Mrose, Mary E. (1952) Hurlbutite, CaBe2(PO4)2, a new mineral. American Mineralogist, 37 (11-12) 931-940
Lindbloom, J. T., Gibbs, G. V., Ribbe, and P. H. (1974) The crystal structure of hurlbutite: A comparison with danburite and anorthite. American Mineralogist, 59 (11-12) 1267-1271
Localities for Hurlbutite
Showing 19 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.
China | |
| Rao +7 other references |
Czech Republic | |
| Stanek J. (1966) |
| Welser |
| Cempírek et al. (1999) |
| Cempírek et al. (2006) +1 other reference |
Finland | |
| RRUFF ID: R070612 +2 other references |
France | |
| Kahou et al. (2026) |
Myanmar | |
Spain | |
| Alfonso et al. (2000) |
| & locality references +1 other reference | |
Sweden | |
| Svensson et al. (2002) |
| Nysten et al. (2006) |
| Langhof et al. (2016) | |
| Wik et al. (2005) | |
| Nysten et al. (2006) |
USA | |
| Thompson et al. (1998) |
| Dallaire (2022) |
| Mrose (1952) +3 other references |
| Rocks & Minerals: 60: 117. +1 other reference |
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Tip Top Mine, Fourmile, Custer Mining District, Custer County, South Dakota, USA