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Ruifrancoite
A valid IMA mineral species
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About Ruifrancoite
Rui R. Franco
Formula:
Ca2(◻,Mn)2(Fe3+,Mn,Mg)4Be4(PO4)6(OH)4(OH,H2O)2 · 4H2O
Colour:
reddish brown
Lustre:
Vitreous
Hardness:
4½
Specific Gravity:
2.88
Crystal System:
Monoclinic
Member of:
Name:
Named in honour of Professor Rui Ribeiro Franco (9 June 1916 - 20 February 2008), in recognition of his outstanding contributions to Brazilian mineralogy and geology.
Unique Identifiers
Mindat ID:
29066
Long-form identifier:
mindat:1:1:29066:3
IMA Classification of Ruifrancoite
Approved
IMA Formula:
Ca2(◻,Mn2+)2(Fe3+,Mn2+,Mg)4Be4(PO4)6(OH)6·4H2O
Approval year:
2006
First published:
2007
Type description reference:
Classification of Ruifrancoite
8.DA.10
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
A : With small (and occasionally larger) cations
8 : PHOSPHATES, ARSENATES, VANADATES
D : Phosphates, etc. with additional anions, with H2O
A : With small (and occasionally larger) cations
42.7.7.4
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
7 : (AB)2(XO4)Zq·xH2O
42 : HYDRATED PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
7 : (AB)2(XO4)Zq·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 |
|---|---|---|
| Rui | 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 Ruifrancoite
Vitreous
Transparency:
Transparent
Colour:
Reddish brown
Streak:
Orange-brown
Hardness:
4½ on Mohs scale
Hardness Data:
Estimated
Tenacity:
Brittle
Density:
2.88(1) g/cm3 (Measured) 2.859 g/cm3 (Calculated)
Optical Data of Ruifrancoite
Type:
Biaxial (+)
RI values:
nα = 1.665(3) nβ = 1.665(3) nγ = 1.682(3)
Max. Birefringence:
δ = 0.017
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:
Very 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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
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.
No measured or calculated 2V is on file for this mineral, so the value used here (0°) is estimated from its recorded refractive indices and optic sign, not from a direct 2V measurement.
Dispersion:
Very strong, r > v
Pleochroism:
Visible
Comments:
Brownish red to light brownish red
Comments:
X = b, Y ^ c ≈ 16°
Chemistry of Ruifrancoite
Mindat Formula:
Ca2(◻,Mn)2(Fe3+,Mn,Mg)4Be4(PO4)6(OH)4(OH,H2O)2 · 4H2O
Element Weights:
Crystallography of Ruifrancoite
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
B2/b
Cell Parameters:
a = 15.911 Å, b = 11.894 Å, c = 6.625 Å
β = 94.5°
β = 94.5°
Ratio:
a:b:c = 1.338 : 1 : 0.557
Unit Cell V:
1250 ų
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 9.485 Å | (44) |
| 5.943 Å | (100) |
| 4.816 Å | (65) |
| 3.169 Å | (44) |
| 3.117 Å | (25) |
| 3.065 Å | (22) |
| 2.777 Å | (41) |
| 2.643 Å | (42) |
Reference:
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites |
Type Occurrence of Ruifrancoite
General Appearance of Type Material:
Needles or laths 1 to 2 microns thick, and up to 100 microns long in fan-shaped botryoids.
Place of Conservation of Type Material:
Museu de Geosciencias, Instituto de Geosciencas, Universidade de Sao Paulo, Brazil (cat.no. DR587). Cotype deposited in the Mineralogical Collection , Technische Universitat Bergakademie Freiberg, Germany (catalog no. 81420)
Geological Setting of Type Material:
Granite pegmatite
Associated Minerals at Type Locality:
Reference:
Synonyms of Ruifrancoite
Other Language Names for Ruifrancoite
Dutch:Ruifrancoiet
German:Ruifrancoit
Relationship of Ruifrancoite to other Species
Member of:
Other Members of Roscherite Group:
| Atencioite | Ca2Fe2+3Mg2Be4(PO4)6(OH)4 · 6H2O | Tric. 1 : P1 |
| Footemineite | Ca2Mn2+Mn2+2Mn2+2Be4(PO4)6(OH)4 · 6H2O | Tric. 1 : P1 |
| Greifensteinite | Ca2Fe2+5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
| Guimarãesite | Ca2Be4Zn5(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
| Okruschite | Ca2Mn2+5Be4(AsO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
| Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/m |
| Zanazziite | Ca2Mg5Be4(PO4)6(OH)4 · 6H2O | Mon. 2/m : B2/b |
Common Associates
Associations Based on Photo Data:
| 21 photos of Ruifrancoite associated with Childrenite | Fe2+Al(PO4)(OH)2 · H2O |
| 14 photos of Ruifrancoite associated with Quartz | SiO2 |
| 12 photos of Ruifrancoite associated with Muscovite | KAl2(AlSi3O10)(OH)2 |
| 9 photos of Ruifrancoite associated with Meurigite-K | KFe3+8(PO4)6(OH)7 · 6.5H2O |
| 6 photos of Ruifrancoite associated with Beryllonite | NaBePO4 |
| 4 photos of Ruifrancoite associated with Feldspar Group | |
| 4 photos of Ruifrancoite associated with Mica Group | |
| 4 photos of Ruifrancoite associated with Hydroxylherderite | CaBe(PO4)(OH) |
| 4 photos of Ruifrancoite associated with 'Meurigite' | |
| 3 photos of Ruifrancoite associated with Cyrilovite | NaFe3+3(PO4)2(OH)4 · 2H2O |
Related Minerals - Strunz-mindat Grouping
| 8.DA.05 | Bearsite | Be2(AsO4)(OH) · 4H2O |
| 8.DA.05 | Moraesite | Be2(PO4)(OH) · 4H2O |
| 8.DA.10 | Zanazziite | Ca2Mg5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Atencioite | Ca2Fe2+3Mg2Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Guimarãesite | Ca2Be4Zn5(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Footemineite | Ca2Mn2+Mn2+2Mn2+2Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Greifensteinite | Ca2Fe2+5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Roscherite | Ca2Mn2+5Be4(PO4)6(OH)4 · 6H2O |
| 8.DA.10 | Okruschite | Ca2Mn2+5Be4(AsO4)6(OH)4 · 6H2O |
| 8.DA.15 | Uralolite | Ca2Be4(PO4)3(OH)3 · 5H2O |
| 8.DA.20 | Weinebeneite | CaBe3(PO4)2(OH)2 · 4H2O |
| 8.DA.25 | Tiptopite | K2(Na,Ca)2Li3Be6(PO4)6(OH)2 · H2O |
| 8.DA.40 | Spencerite | Zn4(PO4)2(OH)2 · 3H2O |
| 8.DA.45 | Glucine | CaBe4(PO4)2(OH)4 · 0.5H2O |
Fluorescence of Ruifrancoite
Not fluorescent
Other Information
Notes:
No gas evolution was observed with HCl treatment.
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 Ruifrancoite
mindat.org URL:
https://www.mindat.org/min-29066.html
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Please feel free to link to this page.
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References for Ruifrancoite
Reference List:
Localities for Ruifrancoite
Showing 3 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.
Brazil (TL) | |
| Atencio et al. (2007) |
| Pavel M. Kartashov analysis |
USA | |
| Dallaire (2022) |
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Sapucaia mine, Sapucaia do Norte, Galiléia, Minas Gerais, Brazil