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Magnesiohongruiite-(Fe3+)
A valid IMA mineral species - pending publication
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Hong-Rui Fan
Formula:
(Mg2Fe3+)Fe3+NbO7(OH)
Colour:
reddish-brown to brown in color
Lustre:
Vitreous
Hardness:
5 - 6
Specific Gravity:
4.373 (Calculated)
Crystal System:
Hexagonal
Member of:
Name:
named in honor of Professor Hong-Rui Fan (born in 1963 in Anhui Province), a distinguished researcher who has made significant contributions to the geological study of the Bayan Obo deposit.
The crystal structure of magnesiohongruiite-(Fe3+) confirms its affiliation with the nolanite supergroup, but its dominant cation occupancy differs markedly from that of other minerals in the supergroup, suggesting that it may represent a potential new mineral group.
Name Encoding
Formatted:
magnesiohongruiite-(Fe3+)
HTML:
magnesiohongruiite-(Fe<sup>3+</sup>)
LaTeX:
magnesiohongruiite-(Fe\$\textasciicircum{}{3+}\$)
Unique Identifiers
Mindat ID:
498743
Long-form identifier:
mindat:1:1:498743:3
IMA Classification of Magnesiohongruiite-(Fe3+)
Approved, Pending publication
Approval year:
2025
Classification of Magnesiohongruiite-(Fe3+)
4.CC.
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : With large and medium-sized cations
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
C : Metal: Oxygen = 2: 3,3: 5, and similar
C : With large and medium-sized cations
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 |
|---|---|---|
| Mhg-Fe3+ | 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 Magnesiohongruiite-(Fe3+)
Vitreous
Transparency:
Translucent
Colour:
Reddish-brown to brown in color
Streak:
Reddish-brown
Hardness:
5 - 6 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
good to fair cleavage on the {001} plane
good to fair cleavage on the {001} plane
Fracture:
Irregular/Uneven
Density:
4.373 g/cm3 (Calculated)
Optical Data of Magnesiohongruiite-(Fe3+)
Reflectivity:
| Wavelength | R1 (%) | R2 (%) |
|---|---|---|
| 470nm | 13.0% | 14.1% |
| 546nm | 12.8% | 13.9% |
| 589nm | 12.8% | 14.0% |
| 650nm | 12.8% | 14.0% |
Graph shows reflectance levels at different wavelengths (in nm). Peak reflectance is 14.1%.
R1 shown in black, R2 shown in red
Colour in reflected light:
dark gray
Pleochroism:
Visible
Comments:
dark orange-red to pale yellow
Chemistry of Magnesiohongruiite-(Fe3+)
Mindat Formula:
(Mg2Fe3+)Fe3+NbO7(OH)
Element Weights:
Crystallography of Magnesiohongruiite-(Fe3+)
Crystal System:
Hexagonal
Class (H-M):
6mm - Dihexagonal Pyramidal
Space Group:
P63mc
Cell Parameters:
a = 5.97109(16) Å, c = 9.4375(3) Å
Ratio:
a:c = 1 : 1.581
Unit Cell V:
291.40 ų (Calculated from Unit Cell)
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 5.166 Å | (39) |
| 3.475 Å | (77) |
| 2.984 Å | (48) |
| 2.681 Å | (100) |
| 2.516 Å | (100) |
| 1.658 Å | (50) |
| 1.522 Å | (57) |
| 1.492 Å | (57) |
Reference:
Comments:
Gandolfi mode on single crystal.
Type Occurrence of Magnesiohongruiite-(Fe3+)
General Appearance of Type Material:
well-formed platy to subrounded single crystals (5-30 μm across).
Place of Conservation of Type Material:
Type material is deposited in the collections of the Geology Museum of the Institute of Geology and Geophysics, Chinese Academy of Sciences, No. 19, Beitucheng Western Road, Chaoyang Distinct, 100029 Beijing, People’s Republic of China, catalogue number M8241 (holotype), and the Geological Museum of China, No. 15, Yangrou Hutong, Xicheng Distinct, 100034 Beijing, People’s Republic of China, catalogue number GMCTM2024011 (cotype)
Geological Setting of Type Material:
calcite-dolomite carbonatite dyke. Magnesiohongruiite-(Fe3+) is typically found at the contact between oboniobite and magnetite
Associated Minerals at Type Locality: