Mccrillisite
A valid IMA mineral species
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About Mccrillisite
Formula:
NaCs(Be,Li)Zr2(PO4)4 · 1-2H2O
Colour:
White to colorless
Lustre:
Vitreous
Hardness:
4 - 4½
Specific Gravity:
3.125
Crystal System:
Tetragonal
Member of:
Name:
In honor of the late Dean McCrillis (February 8, 1931 in Quincy, Massachusetts - January 15, 1989), mineral dealer and his son, Philip.
Type Locality:
Unique combination of elements. The only known Cs phosphate mineral. Also the sixth non-silicate oxysalt with species-defining Cs, the other ones being cesiodymite (sulphate), caesiumpharmacosiderite (arsenate), londonite and ramanite-(Cs) (borates), and margaritasite (vanadate).
Unique Identifiers
Mindat ID:
7174
Long-form identifier:
mindat:1:1:7174:7
IMA Classification of Mccrillisite
Classification of Mccrillisite
8.CA.20
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
A : With small and large/medium cations
40.5.4.2
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
40 : HYDRATED NORMAL PHOSPHATES,ARSENATES AND VANADATES
5 : AXO4·xH2O
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 |
|---|---|---|
| Mcr | 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 Mccrillisite
Vitreous
Transparency:
Transparent, Translucent
Colour:
White to colorless
Streak:
White
Hardness:
4 - 4½ on Mohs scale
Cleavage:
None Observed
Fracture:
Conchoidal
Density:
3.125(5) g/cm3 (Measured) 3.30 g/cm3 (Calculated)
Optical Data of Mccrillisite
Type:
Uniaxial (+)
RI values:
nω = 1.634(2) nε = 1.645(2)
Max. Birefringence:
δ = 0.011
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 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.
Comments:
Anomalously biaxial, with 2V to 5 degrees.
Chemistry of Mccrillisite
Mindat Formula:
NaCs(Be,Li)Zr2(PO4)4 · 1-2H2O
Element Weights:
Common Impurities:
Al,Ca,Mg,Mn,Fe,Sr,K,Zn,Hf,Rb,F
Crystallography of Mccrillisite
Crystal System:
Tetragonal
Class (H-M):
4/mmm(4/m2/m2/m) - Ditetragonal Dipyramidal
Space Group:
I41/amd
Setting:
I41/amd
Cell Parameters:
a = 6.573(2) Å, c = 17.28(2) Å
Ratio:
a:c = 1 : 2.629
Unit Cell V:
746.57 ų (Calculated from Unit Cell)
Z:
2
Morphology:
Bipyramidal. The dominant form is {111}, and the minor form is {001}.
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 3.060 Å | (100) |
| 6.159 Å | (90) |
| 4.326 Å | (80) |
| 3.281 Å | (80) |
| 4.099 Å | (40) |
| 2.896 Å | (30) |
| 1.849 Å | (30) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 22 : Hydration and low-? subsurface aqueous alteration (see also #23) |
Type Occurrence of Mccrillisite
General Appearance of Type Material:
Bipyramidal crystals as much as 1.2 mm in maximum dimension. Many crystals have a crackled appearance.
Place of Conservation of Type Material:
National Museum of Natural History (Smithsonian), Washington, D.C., USA, 170853.
Geological Setting of Type Material:
Late-staqe hydrothermal alteration of earlier-formed Zr-bearing minerals in the pegmatite.
Associated Minerals at Type Locality:
Synonyms of Mccrillisite
Other Language Names for Mccrillisite
Relationship of Mccrillisite to other Species
Member of:
Other Members of Gainesite Group:
Common Associates
Related Minerals - Strunz-mindat Grouping
| 8.CA. | Apexite | NaMg(PO4) · 9H2O |
| 8.CA. | Brandãoite | BeAl2(PO4)2(OH)2(H2O)5 |
| 8.CA. | Davidlloydite | Zn3(AsO4)2 · 4H2O |
| 8.CA.05 | Parafransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.05 | Fransoletite | Ca3Be2(PO4)2(PO3OH)2 · 4H2O |
| 8.CA.10 | Ehrleite | Ca4Be3Zn2(PO4)6 · 9H2O |
| 8.CA.15 | Faheyite | Be2Mn2+Fe3+2(PO4)4 · 6H2O |
| 8.CA.20 | Gainesite | Na(Na,K)(Be,Li)Zr2(PO4)4 · 1.5-2H2O |
| 8.CA.20 | Selwynite | NaK(Be,Al)Zr2(PO4)4 · 2H2O |
| 8.CA.25 | Pahasapaite | Li8(Ca,Li,K)10.5Be24(PO4)24 · 38H2O |
| 8.CA.30 | Nizamoffite | Mn2+Zn2(PO4)2(H2O)4 |
| 8.CA.30 | Arsenohopeite | Zn3(AsO4)2 · 4H2O |
| 8.CA.30 | Hopeite | ZnZn2(PO4)2 · 4H2O |
| 8.CA.35 | Warikahnite | Zn3(AsO4)2 · 2H2O |
| 8.CA.40 | Phosphophyllite | Zn2Fe 2+(PO4)2 · 4H2O |
| 8.CA.42 | Steinmetzite | Zn2Fe3+(PO4)2(OH) · 3H2O |
| 8.CA.45 | Parascholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.45 | Scholzite | CaZn2(PO4)2 · 2H2O |
| 8.CA.50 | Keyite | Cu2+3Zn4Cd2(AsO4)6 · 2H2O |
| 8.CA.55 | Pushcharovskite | K0.6Cu18[AsO2(OH)2]4[AsO3OH]10(AsO4)(OH)9.6 · 18.6H2O |
| 8.CA.60 | Prosperite | Ca2Zn4(AsO4)4 · H2O |
| 8.CA.65 | Gengenbachite | KFe3+3(PO3OH)4[PO2(OH)2]2 · 6H2O |
| 8.CA.70 | Parahopeite | Zn3(PO4)2 · 4H2O |
| 8.CA.70 | Reaphookhillite | MgZn2(PO4)2 · 4H2O |
| 8.CA.75 | Stergiouite | CaZn2(AsO4)2 · 4H2O |
| 8.CA.80 | Limousinite | BaCa[Be4P4O16] · 6H2O |
| 8.CA.85 | Minjiangite | BaBe2(PO4)2 |
| 8.CA.85 | Wilancookite | (Ba5Li2◻)Ba6Be24P24O96 · 26H2O |
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 Mccrillisite
mindat.org URL:
https://www.mindat.org/min-7174.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 Mccrillisite
Localities for Mccrillisite
Showing 1 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.
USA (TL) | |
| Foord et al. (1994) +1 other reference |
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Mount Mica Quarry, Paris, Oxford County, Maine, USA