Isoclasite
A valid IMA mineral species - grandfathered - questionable
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Formula:
Ca2(PO4)(OH) · 2H2O
Colour:
colourless, snow-white; colourless in transmitted light.
Lustre:
Vitreous, Pearly
Hardness:
1 - 1½
Specific Gravity:
2.92
Crystal System:
Monoclinic
Name:
From the Greek for "equal fracture," in allusion to the cleavage.
This page provides mineralogical data about Isoclasite.
Unique Identifiers
Mindat ID:
2051
Long-form identifier:
mindat:1:1:2051:6
GUID
(UUID V4):
(UUID V4):
26c73443-0b92-47d2-9bac-3aec745c50f8
IMA Classification of Isoclasite
Approved, 'Grandfathered' (first described prior to 1959), Questionable
Classification of Isoclasite
8.DN.10
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
N : With only large cations
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
N : With only large cations
42.6.2.1
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
6 : A2(XO4)Zq·xH2O
19.4.4
19 : Phosphates
4 : Phosphates of Ca
19 : Phosphates
4 : Phosphates of Ca
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 |
|---|---|---|
| Icl | 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 Isoclasite
Vitreous, Pearly
Transparency:
Transparent
Comment:
Lustre pearly on cleavages.
Colour:
colourless, snow-white; colourless in transmitted light.
Hardness:
1 - 1½ on Mohs scale
Cleavage:
Distinct/Good
On {010}, distinct.
On {010}, distinct.
Density:
2.92 g/cm3 (Measured)
Optical Data of Isoclasite
Type:
Biaxial (+)
RI values:
nα = 1.565 nβ = 1.568 nγ = 1.580
2V:
Calculated: 54°
Max Birefringence:
δ = 0.015
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
r > v strong
Chemistry of Isoclasite
Mindat Formula:
Ca2(PO4)(OH) · 2H2O
Elements listed:
Crystallography of Isoclasite
Crystal System:
Monoclinic
Morphology:
Crystals minute, dull, prismatic [001]; also occurs as cotton-like fibers.
Comment:
inferred from optical data
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Type Occurrence of Isoclasite
General Appearance of Type Material:
Transparent crystals, to 4 cm in length, partly altered to a milky colored material.
Geological Setting of Type Material:
Reddish dolomite vein in hornfels.
Associated Minerals at Type Locality:
Reference:
Sandberger, F., (1870): "Ueber Isoklas und Kollophan, zwei neue Phosphate": J. prakt Chemie, Neue Folge, 2,125-130 (as Isoklas)
Other Language Names for Isoclasite
Spanish:Isoclasita
Related Minerals - Strunz-mindat Grouping
| 8.DN. | Loomisite | Ba[Be2P2O8] · H2O |
| 8.DN.05 | Natrophosphate | Na6+xHxF(PO4)2 · (19+x)H2O |
| 8.DN.15 | Lermontovite | U(PO4)(OH) · H2O |
| 8.DN.15 | Urphoite | U4+6(PO4)7(OH)3 · 4H2O |
| 8.DN.20 | Vyacheslavite | U(PO4)(OH) |
Other Information
Notes:
Readily 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 Isoclasite
mindat.org URL:
https://www.mindat.org/min-2051.html
Please feel free to link to this page.
Please feel free to link to this page.
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External Links:
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References for Isoclasite
Localities for Isoclasite
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 | |
| Sorrell (n.d.) | |
| Sorrell (n.d.) | |
Czech Republic (TL) | |
| Sandberger et al. (1870) +1 other reference |
Portugal | |
| |
| Figueiras +4 other references |
