Davidbrownite-(NH4)
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About Davidbrownite-(NH4)
Formula:
(NH4)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4 · 3H2O
Colour:
Light green-blue
Lustre:
Vitreous
Hardness:
2
Specific Gravity:
2.12
Crystal System:
Monoclinic
Name:
Named in honor of I. David Brown (b. 11 April 1932, Edgeware, Middlesex, UK) British-Canadian crystallographer and professor at McMaster University, Hamilton, Ontario, Canada. Dr. Brown is well known for developing Bond-Valence Theory used by mineralogical crystallographers worldwide.
New structure type. Unique combination of elements (compare rowleyite, though). The first vanadium-bearing oxalate mineral. The first approved organic vanadium mineral.
Classification of Davidbrownite-(NH4)
Physical Properties of Davidbrownite-(NH4)
Vitreous
Colour:
Light green-blue
Streak:
White
Hardness:
2 on Mohs scale
Tenacity:
Brittle
Cleavage:
Distinct/Good
Probably {100} and {001}
Probably {100} and {001}
Fracture:
Splintery
Density:
2.12(2) g/cm3 (Measured)
Optical Data of Davidbrownite-(NH4)
Type:
Biaxial (+)
RI values:
nα = 1.540(2) nβ = 1.550(5) nγ = 1.582(2)
2V:
Measured: 58.5° (5)
Max Birefringence:
δ = 0.042
Image shows birefringence interference colour range (at 30µm thickness)
and does not take into account mineral colouration.
and does not take into account mineral colouration.
Surface Relief:
Low
Dispersion:
moderate, r>v
Pleochroism:
Visible
Comments:
X = pale blue, Y = nearly colorless, Z = lightblue; Y
Comments:
Z=b,Y≈a
Chemical Properties of Davidbrownite-(NH4)
Formula:
(NH4)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4 · 3H2O
IMA Formula:
(NH4)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4 · 3H2O
Crystallography of Davidbrownite-(NH4)
Crystal System:
Monoclinic
Class (H-M):
2/m - Prismatic
Space Group:
P21/b
Setting:
P21/c
Cell Parameters:
a = 10.356(6) Å, b = 8.923(5) Å, c = 13.486(7) Å
β = 92.618(9)°
β = 92.618(9)°
Ratio:
a:b:c = 1.161 : 1 : 1.511
Unit Cell V:
1244.9 ų
Z:
2
X-Ray Powder Diffraction
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 10.39 Å | (100) |
| 6.73 Å | (50) |
| 5.97 Å | (34) |
| 3.789 Å | (35) |
| 3.160 Å | (47) |
| 3.104 Å | (42) |
| 3.043 Å | (35) |
| 2.977 Å | (44) |
Type Occurrence of Davidbrownite-(NH4)
General Appearance of Type Material:
Needles or narrow blades up to about 0.2 mm in length
Place of Conservation of Type Material:
Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA, catalogue numbers 66951, 66955 and 66959 (cotypes)
Geological Setting of Type Material:
Bat-guano-related, post-mining assemblage
Associated Minerals at Type Locality:
Reference:
Kampf, A.R., Cooper, M.A., Rossman, G.R., Nash, B.P., Hawthorne, F.C., Marty, J. (2019) Davidbrownite-(NH4), (NH4,K)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4·3H2O, a new phosphate–oxalate mineral from the Rowley mine, Arizona, USA. Mineralogical Magazine: 83: 869-877.
Synonyms of Davidbrownite-(NH4)
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.
References for Davidbrownite-(NH4)
Reference List:
Sort by Year (asc) | by Year (desc) | by Author (A-Z) | by Author (Z-A)
Kampf, A.R., Cooper, M.A., Rossman, G.R., Nash, B.P., Hawthorne, F.C. and Marty, J. (2019) Davidbrownite, IMA 2018-129. CNMNC Newsletter No. 47, February 2019: 203. European Journal of Mineralogy: 31: 199–204.
Kampf, A.R., Cooper, M.A., Rossman, G.R., Nash, B.P., Hawthorne, F.C., Marty, J. (2019) Davidbrownite-(NH4), (NH4,K)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4·3H2O, a new phosphate–oxalate mineral from the Rowley mine, Arizona, USA. Mineralogical Magazine: 83: 869-877.
Internet Links for Davidbrownite-(NH4)
mindat.org URL:
https://www.mindat.org/min-53370.html
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Localities for Davidbrownite-(NH4)
symbol to view information about a locality.
The Locality List
- This locality has map coordinates listed.
- This locality has estimated coordinates.
ⓘ - Click for 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) | |
| Kampf, A.R., Cooper, M.A., Rossman, G.R., Nash, B.P., Hawthorne, F.C., Marty, J. (2019) Davidbrownite-(NH4), (NH4,K)5(V4+O)2(C2O4)[PO2.75(OH)1.25]4·3H2O, a new phosphate–oxalate mineral from the Rowley mine, Arizona, USA. Mineralogical Magazine: 83: 869-877. |
125 foot level, Rowley Mine, Theba, Painted Rock Mining District, Painted Rock Mountains, Maricopa Co., Arizona, USA