Sherwoodite
A valid IMA mineral species - grandfathered
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About Sherwoodite
Formula:
Ca5.5(AlV4+V5+12O39) · 28H2O
formerly given as Ca4.5(AlV#4+#2V#5+#12O40)·28H2O
Colour:
Dark bluish black (fresh), blue-green, yellow-green (altered)
Lustre:
Vitreous, Earthy
Hardness:
2
Specific Gravity:
2.8
Crystal System:
Tetragonal
Name:
For Alexander M. Sherwood (b. 1888), an analytical chemist of the United States Geological Survey (USGS).
This mineral contains aluminovanadate(IV,V) polyanions, consisting of 14 (VO6) octahedra condensed by edge-sharing around a central (AlO6) octahedron (Evans and Konnert, 1978).
The structure is based on [AlV4+V5+12O39]11− vanadoaluminate anion, as redefined in 2023.
The structure is based on [AlV4+V5+12O39]11− vanadoaluminate anion, as redefined in 2023.
Unique Identifiers
Mindat ID:
3637
Long-form identifier:
mindat:1:1:3637:1
GUID
(UUID V4):
(UUID V4):
6a657b0d-ff84-436d-b203-2de011516a80
IMA Classification of Sherwoodite
Approved, 'Grandfathered' (first described prior to 1959)
IMA Formula:
Ca4.5AlV4+2V5+12O40 · 28H2O
First published:
1958
Classification of Sherwoodite
4.HC.15
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates
4 : OXIDES (Hydroxides, V[5,6] vanadates, arsenites, antimonites, bismuthites, sulfites, selenites, tellurites, iodates)
H : V[5,6] Vanadates
C : [6]-Sorovanadates
47.2.4.1
47 : VANADIUM OXYSALTS
2 : Anhydrous Vanadium Oxysalts Containing Hydroxyl or Halogen
47 : VANADIUM OXYSALTS
2 : Anhydrous Vanadium Oxysalts Containing Hydroxyl or Halogen
21.2.9
21 : Vanadates (and vanadates with arsenate or phosphate)
2 : Vanadates of Mg, Ca, Sr or Ba
21 : Vanadates (and vanadates with arsenate or phosphate)
2 : Vanadates of Mg, Ca, Sr or Ba
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 |
---|---|---|
Swd | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
Pronunciation of Sherwoodite
Pronunciation:
Play | Recorded by | Country |
---|---|---|
Jolyon Ralph | United Kingdom |
Physical Properties of Sherwoodite
Vitreous, Earthy
Transparency:
Translucent
Colour:
Dark bluish black (fresh), blue-green, yellow-green (altered)
Streak:
Pale blue.
Hardness:
2 on Mohs scale
Fracture:
Irregular/Uneven, Sub-Conchoidal
Density:
2.8(1) g/cm3 (Measured) 2.56 g/cm3 (Calculated)
Optical Data of Sherwoodite
Type:
Uniaxial (-)
RI values:
nω = 1.765(3) nε = 1.735 - 1.738
Max Birefringence:
δ = 0.030
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:
High
Pleochroism:
Visible
Comments:
O = green to yellow-brown; E = blue to deep blue-green.
Chemistry of Sherwoodite
Mindat Formula:
Ca5.5(AlV4+V5+12O39) · 28H2O
formerly given as Ca4.5(AlV#4+#2V#5+#12O40)·28H2O
formerly given as Ca4.5(AlV#4+#2V#5+#12O40)·28H2O
Chemical Analysis
Empirical formulas:
Sample ID | Empirical Formula |
---|---|
1 | (Ca4.26Mg1.09Na0.35K0.04Sr0.03)[Al0.87(V4+V5+12)O39]·28.15H2O |
Sample references:
ID | Locality | Reference | Notes |
---|---|---|---|
1 | Peanut Mine, Bull Canyon, Uravan Mining District, Montrose County, Colorado, USA | empirical formula basis: 12 V atoms pfu; the locality is given in the abstract as "Uravan Mineral Belt" |
Crystallography of Sherwoodite
Crystal System:
Tetragonal
Class (H-M):
4/mmm (4/m 2/m 2/m) - Ditetragonal Dipyramidal
Space Group:
I41/amd
Setting:
I41/amd
Cell Parameters:
a = 27.9085(7) Å, c = 13.8090(5) Å
Ratio:
a:c = 1 : 0.495
Unit Cell V:
10,755.61 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Crystals are equant or slightly flattened. Type material crystals display only two forms: m{110} and d{011}.
Comment:
crystallizes as a structural variation of the putative (AlV4+,5+14O40)n− vanadoaluminate complex
Crystal Structure
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Data courtesy of the American Mineralogist Crystal Structure Database. Click on an AMCSD ID to view structure
ID | Species | Reference | Link | Year | Locality | Pressure (GPa) | Temp (K) |
---|---|---|---|---|---|---|---|
0000685 | Sherwoodite | Evans H T, Konnert J A (1978) The crystal chemistry of sherwoodite, a calcium 14-vanadoaluminate heteropoly complex American Mineralogist 63 863-868 | 1978 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Powder Diffraction Data:
d-spacing | Intensity |
---|---|
12.3 Å | (strong) |
10.0 Å | (strong) |
9.3 Å | (moderately strong) |
2.61 Å | (moderate) |
2.10 Å | (moderate broad) |
7.8 Å | (weak) |
7.1 Å | (weak) |
Comments:
Colorado Plateau, USA. The data are from the type description.
Geological Environment
Paragenetic Mode(s):
Paragenetic Mode | Earliest Age (Ga) |
---|---|
Stage 7: Great Oxidation Event | <2.4 |
47a : [Near-surface hydration of prior minerals] | |
47e : [Vanadates, chromates, manganates] | |
Stage 10a: Neoproterozoic oxygenation/terrestrial biosphere | <0.6 |
53 : Other minerals with taphonomic origins | <0.4 |
Geological Setting:
sandstone uranium deposits
Type Occurrence of Sherwoodite
General Appearance of Type Material:
Equant or slightly flattened crystals, occurring singly and as polycrystalline aggregates.
Place of Conservation of Type Material:
National Museum of Natural History, Washington, D.C., USA, 115883, 121951.
Geological Setting of Type Material:
Oxidation of vanadium minerals on fracture surfaces in sandstones and mineralized coalified wood.
Associated Minerals at Type Locality:
Other Language Names for Sherwoodite
German:Sherwoodit
Russian:Шервудит
Simplified Chinese:柱水钒钙矿
Spanish:Sherwoodita
Traditional Chinese:柱水釩鈣礦
Common Associates
Associated Minerals Based on Photo Data:
Related Minerals - Strunz-mindat Grouping
4.HC. | Beckettite | Ca2V6Al6O20 |
4.HC. | Ammoniolasalite | (NH4)2Mg2(H2O)20] [V10O28] |
4.HC. | Protocaseyite | [Al4(OH)6(H2O)12][V10O28] · 8H2O |
4.HC.05 | Pascoite | Ca2Ca(V10O28) · 17H2O |
4.HC.05 | Lasalite | Na2Mg2(V10O28) · 20H2O |
4.HC.05 | Magnesiopascoite | Ca2Mg(V10O28) · 16H2O |
4.HC.05 | Rakovanite | (NH4)3Na3(V10O28) · 12H2O |
4.HC.05 | Hughesite | Na3Al(V10O28) · 22H2O |
4.HC.05 | Hydropascoite | Ca3(V10O28) · 24H2O |
4.HC.10 | Hummerite | K2Mg2(V10O28) · 16H2O |
4.HC.20 | Bluestreakite | K4Mg2(V4+2V5+8O28) · 14H2O |
4.HC.25 | Wernerbaurite | {(NH4)2[Ca2(H2O)14](H2O)2}{V10O28} |
4.HC.25 | Burroite | Ca2(NH4)2(V10O28) · 15H2O |
4.HC.30 | Caseyite | [(V5+O2)Al10-x(OH)20-2x(H2O)18-2x]2[H2V4+V5+9O28][V5+10O28]2(Na,K,Ca)2-y(SO4)2-z · (60+8x+y+4z)H2O (x = 0-2.5; y = 0-2; z = 0-2) |
4.HC.35 | Gunterite | Na4Ca(V10O28) · 20H2O |
4.HC.40 | Kokinosite | Na2Ca2(V10O28) · 24H2O |
4.HC.45 | Nashite | Na3Ca2[(V5+9V4+)O28] · 24H2O |
4.HC.50 | Okieite | Mg3[V10O28] · 28H2O |
4.HC.55 | Postite | Mg(H2O)6Al2(OH)2(H2O)8(V10O28) · 13H2O |
4.HC.60 | Schindlerite | {(NH4)4Na2(H2O)10}{V10O28} |
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 Sherwoodite
mindat.org URL:
https://www.mindat.org/min-3637.html
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References for Sherwoodite
Reference List:
Localities for Sherwoodite
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).
Struck out - Mineral was erroneously reported from this locality.
Faded * - Never found at this locality but inferred to have existed at some point in the past (e.g. from pseudomorphs).
All localities listed without proper references should be considered as questionable.
All localities listed without proper references should be considered as questionable.
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Firefly–Pigmay Mine, La Sal Creek Mining District, San Juan County, Utah, USA