Mikehowardite
A valid IMA mineral species
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About Mikehowardite
J. Michael (Mike) Howard
Formula:
Fe3+4(V5+O4)4(H2O)2 · H2O
Colour:
Very dark brown; dark brown-red
Lustre:
Sub-Adamantine
Hardness:
3½
Specific Gravity:
3.19
Crystal System:
Triclinic
Name:
Named in honor of J. Michael (Mike) Howard, former geologist with the Arkansas Geological Commission. He is an expert on Magnet Cove.
Structurally related to schubnelite: both bear edge-sharing dimers of Fe3+O6 octahedra, linked by distorted VO4 tetrahedra.
Co-described with donowensite with which it is intimately associated.
Co-described with donowensite with which it is intimately associated.
Unique Identifiers
Mindat ID:
55313
Long-form identifier:
mindat:1:1:55313:7
IMA Classification of Mikehowardite
Classification of Mikehowardite
8.C0.
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
0 :
8 : PHOSPHATES, ARSENATES, VANADATES
C : Phosphates without additional anions, with H2O
0 :
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 |
|---|---|---|
| Mhw | 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 Mikehowardite
Sub-Adamantine
Colour:
Very dark brown; dark brown-red
Streak:
Yellow-orange
Hardness:
3½ on Mohs scale
Cleavage:
Very Good
({100} very good; also two other undetermined good cleavage systems
({100} very good; also two other undetermined good cleavage systems
Fracture:
Irregular/Uneven, Step-Like
Density:
3.19(2) g/cm3 (Measured)
Optical Data of Mikehowardite
Type:
Biaxial
Pleochroism:
Weak
Comments:
shades of brown-orange
Comments:
Gladstone-Dale n(av) = 2.034
Chemistry of Mikehowardite
Mindat Formula:
Fe3+4(V5+O4)4(H2O)2 · H2O
Element Weights:
Elements listed:
Crystallography of Mikehowardite
Crystal System:
Triclinic
Class (H-M):
1 - Pinacoidal
Space Group:
P1
Cell Parameters:
a = 6.655(2) Å, b = 6.669(1) Å, c = 9.003(2) Å
α = 76.515(5)°, β = 84.400(6)°, γ = 75.058(5)°
α = 76.515(5)°, β = 84.400(6)°, γ = 75.058(5)°
Ratio:
a:b:c = 0.998 : 1 : 1.35
Unit Cell V:
375.12 ų (Calculated from Unit Cell)
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 8.799 Å | (86) |
| 6.449 Å | (100) |
| 3.693 Å | (29) |
| 3.198 Å | (88) |
| 2.982 Å | (50) |
| 2.909 Å | (59) |
| 2.792 Å | (31) |
| 2.145 Å | (30) |
Type Occurrence of Mikehowardite
General Appearance of Type Material:
Equant prisms, up to 0.15 mm in length.
Place of Conservation of Type Material:
Cotype material is deposited in the mineralogical collections of the Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 75041 and 75042.
Geological Setting of Type Material:
Oxidation of primary ore V minerals contained in altered rocks contacting with an igneous complex.
Associated Minerals at Type Locality:
Synonyms of Mikehowardite
Other Language Names for Mikehowardite
Dutch:Mikehowardiet
German:Mikehowardit
Common Associates
Associations Based on Photo Data:
| 5 photos of Mikehowardite associated with Bokite | (Al,Fe)1.3(V5+,V4+,Fe3+)8O20 · 7.5H2O |
| 2 photos of Mikehowardite associated with Donowensite | Ca(H2O)3Fe3+2(V2O7)2 |
Related Minerals - Strunz-mindat Grouping
| 8.C0. | Batagayite | CaZn2(Zn,Cu)6(PO4)4[PO3OH]3 · 12H2O |
| 8.C0. | Domerockite | Cu4(AsO4)(AsO3OH)(OH)3 · H2O |
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 Mikehowardite
mindat.org URL:
https://www.mindat.org/min-55313.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 Mikehowardite
Reference List:
Miyawaki, Ritsuro, Hatert, Frédéric, Pasero, Marco, Mills, Stuart J. (2021) IMA Commission on New Minerals, Nomenclature and Classification (CNMNC) – Newsletter 59. European Journal of Mineralogy, 33 (1) 139-143 doi:10.5194/ejm-33-139-2021
Kampf, Anthony R., Hughes, John M., Nash, Barbara P., Smith, Jason B. (2022) Donowensite, Ca(H2O)3Fe3+2(V2O7)2, and mikehowardite, Fe3+4(VO4)4(H2O)2·H2O, two new vanadium minerals from the Wilson Springs Vanadium Mine, Wilson Springs, Arkansas, USA. The Canadian Mineralogist, 60 (3) 543-554 doi:10.3749/canmin.210015
Localities for Mikehowardite
Showing 2 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.
China | |
| Christian Rewitzer collection |
USA (TL) | |
| Miyawaki et al. (2021) +1 other reference |
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Qinglong Mine, Dachang Sb ore field, Qinglong County, Qianxinan, Guizhou, China