Where it forms, where it's found
- Type locality
- Penrice marble quarry
- Penrice
- Barossa Council
- South Australia
- Australia
-34.4817°, 139.0467°
2recorded occurrences
Physical
Optical
- Optical type
- Isotropic
- Principal indices
- n 1.33 – 1.40
- Pleochroism
- Non-pleochroic
- Notes
Originally thought to be biaxial (+), with alpha 1.566, beta 1.572, gamma 1.584, 2V(meas.) 70°, 2V(calc.) 71°. Weak pleochroism, with X = colourless, Y = colourless to pale yellow, Z = colourless.
PPL intrinsic colour; no change on stage rotation
XPL extinct at every orientation
- Single index
- n = 1.365
Crystallography
- Morphology
Refers to original erroneous description: Platy crystals with the forms (010) (prominent), (101), (10) and (100) (rare), and also occurs as replacements of an unknown pre-existing mineral.
- Type-locality form
White
- Comment
Formerly thought to be crystalline, triclinic, a = 13.303(1), b = 27.020(2), c = 6.1070(7), α = 89.64(1), β = 83.44(1), γ = 80.444(8); now proven to be actually amorphous (Grey et al., 2022).
Chemical composition
Synonyms
- Angastoniet
- Angastonitt
- IMA2008-008
In other languages
- German
- Angastonit · IMA 2008-008
- Italian
- angastonite
Classification
Strunz
10th ed.8.DL.25
- 8Phosphates, Arsenates, VanadatesClass
- 8.DPhosphates, etc. with additional anions, with H2ODivision
- 8.DLWith large and medium-sized cations, (OH, etc.):RO4 = 2:1Group
- 8.DL.25AngastoniteSpecies
Dana
8th ed.42.07.22
- 42Hydrated Phosphates, Etc.containing Hydroxyl or HalogenClass
- 42.07(AB)2(XO4)Zq·xH2OType
- 42.07.22— unnamed intermediate level —Group
- 42.07.22AngastoniteSpecies
Literature, links & citation
Citations
- 2008Mills, S. J., Groat, L. A., Wilson, S. A., Birch, W. D., Whitfield, P. S., Raudsepp, M. (2008) Angastonite, CaMgAl2(PO4)2(OH)4·7H2O: a new phosphate mineral from Angaston, South Australia. Mineralogical Magazine, 72 (5) 1011-1020 doi:10.1180/minmag.2008.072.5.1011 DOI: 10.1180/minmag.2008.072.5.1011
- 2022(2022) Angastonite. Handbook of Mineralogy. Mineralogical Society of America
- 2022Grey, Ian Edward, Elliott, Peter, Mumme, William Gus, MacRae, Colin M., Kampf, Anthony R., Mills, Stuart J. (2022) Redefinition of angastonite, CaMgAl2(PO4)2(OH)4 ⋅ 7H2O, as an amorphous mineral. European Journal of Mineralogy, 34 (2) 215-221 doi:10.5194/ejm-34-215-2022 DOI: 10.5194/ejm-34-215-2022
Cite this entry
@misc{mineral2026,
author = {Mineral Index editorial board},
title = {Angastonite — Mineral Index},
year = {2026},
url = {https://mineralindex.org/minerals/angastonite-35972},
note = {Accessed 2026-05-11}
}