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Collinsite
A valid IMA mineral species - grandfathered
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About Collinsite
William H. Collins
Formula:
Ca2Mg(PO4)2 · 2H2O
Colour:
Light brown; light yellow-brown to colourless in transmitted light.
Lustre:
Silky
Hardness:
3 - 3½
Specific Gravity:
2.99
Crystal System:
Triclinic
Member of:
Name:
Named by E. Poitevin and M.F. Connor in 1924 in honor of William Henry Collins (26 October 1878, near Chatsworth, Ontario, Canada - January 14, 1937, Ottawa, Ontario, Canada), geologist and Director, Geological Survey of Canada (1920-1936).
Unique Identifiers
Mindat ID:
1109
Long-form identifier:
mindat:1:1:1109:5
IMA Classification of Collinsite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca2Mg(PO4)2·2H2O
First published:
1924
Classification of Collinsite
8.CG.05
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 1:1
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
G : With large and medium-sized cations, RO4:H2O = 1:1
40.2.2.3
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2 : AB2(XO4)2·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
2 : AB2(XO4)2·xH2O
19.14.20
19 : Phosphates
14 : Phosphates of Fe and other metals
19 : Phosphates
14 : Phosphates of Fe and other metals
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 |
|---|---|---|
| Coll | 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 Collinsite
Silky
Transparency:
Translucent
Colour:
Light brown; light yellow-brown to colourless in transmitted light.
Streak:
White
Hardness:
3 - 3½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Imperfect/Fair
On {001} and {010}, fair.
On {001} and {010}, fair.
Density:
2.99 g/cm3 (Measured) 3.04 g/cm3 (Calculated)
Optical Data of Collinsite
Type:
Biaxial (+)
RI values:
nα = 1.632 nβ = 1.642 nγ = 1.657
2V:
Measured: 80°
Max. Birefringence:
δ = 0.025
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:
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:
r < v strong
Chemistry of Collinsite
Mindat Formula:
Ca2Mg(PO4)2 · 2H2O
Element Weights:
Crystallography of Collinsite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 5.73 Å, b = 6.78 Å, c = 5.44 Å
α = 97.29°, β = 108.56°, γ = 107.28°
α = 97.29°, β = 108.56°, γ = 107.28°
Ratio:
a:b:c = 0.845 : 1 : 0.802
Unit Cell V:
185.49 ų (Calculated from Unit Cell)
Morphology:
Radial blades or lath-like fibers elongated [100], comprising layers.
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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Labels
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Console Off | On | Grey | Yellow
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) |
|---|---|---|---|---|---|---|---|
| 0006118 | Collinsite | Herwig S, Hawthorne F C (2006) The topology of hydrogen bonding in brandtite, collinsite and fairfieldite The Canadian Mineralogist 44 1181-1196 |  | 2006 | Rapid Creek, Yukon Territory, Canada | 0 | 293 |
| 0012055 | Collinsite | Brotherton P D, Maslen E N, Pryce M W, White A H (1974) Crystal structure of collinsite Australian Journal of Chemistry 27 653-656 | 1974 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.04 Å | (100) |
| 2.682 Å | (90) |
| 2.713 Å | (80) |
| 2.735 Å | (60) |
| 3.24 Å | (50) |
| 3.14 Å | (50) |
| 3.02 Å | (50) |
Comments:
Milgun Station, Australia. Data from Bridge and Pryce (1974).
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 Collinsite
General Appearance of Type Material:
Layers in phosphate nodules, consisting of elongated blades to 1 cm in length by 0.5 mm in width.
Place of Conservation of Type Material:
No designated type material.
Geological Setting of Type Material:
Vein deposit in andesite.
Associated Minerals at Type Locality:
Other Language Names for Collinsite
Relationship of Collinsite to other Species
Member of:
Other Members of Collinsite Group:
| Anorthoroselite | Ca2Co(AsO4)2 · 2H2O | Tric. |
| Cassidyite | Ca2Ni(PO4)2 · 2H2O | Tric. |
| Fairfieldite | Ca2Mn2+(PO4)2 · 2H2O | Tric. 1 : P1 |
| Gaitite | Ca2Zn(AsO4)2 · 2H2O | Tric. 1 : P1 |
| Hillite | Ca2Zn(PO4)2 · 2H2O | Tric. 1 : P1 |
| Messelite | Ca2Fe2+(PO4)2 · 2H2O | Tric. 1 : P1 |
| Nickeltalmessite | Ca2Ni(AsO4)2 · 2H2O | Tric. 1 : P1 |
Francois Lake phosphate occurrence, Francois Lake, Omineca Mining Division, British Columbia, Canada