Rockbridgeite
A valid IMA mineral species - grandfathered
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About Rockbridgeite
Seal of Rockbridge Co., Virginia, USA
Formula:
(Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5
Previously given as Fe2+Fe3+4(PO4)3(OH)5.
Colour:
Dark green, olive-green, brown, yellow-brown, greenish black, black
Lustre:
Sub-Vitreous, Resinous, Waxy, Greasy, Silky
Hardness:
3½ - 4½
Specific Gravity:
3.45 - 3.6
Crystal System:
Orthorhombic
Member of:
Name:
Named in 1949 by Clifford Frondel for the type locality at the Midvale Mine, South Mountain, Midvale, Rockbridge County, Virginia, USA.
Isostructural with:
Rockbridgeite Group. Frondelite-Rockbridgeite Series.
The Fe2+-analogue of frondelite and plimerite.
A secondary mineral resulting from the alteration of primary phosphates.
Visually similar to dufrénite and natrodufrénite.
Compare chemically very similar ferrorockbridgeite.
The Fe2+-analogue of frondelite and plimerite.
A secondary mineral resulting from the alteration of primary phosphates.
Visually similar to dufrénite and natrodufrénite.
Compare chemically very similar ferrorockbridgeite.
Unique Identifiers
Mindat ID:
3433
Long-form identifier:
mindat:1:1:3433:9
IMA Classification of Rockbridgeite
Approved, 'Grandfathered' (first described prior to 1959)
Classification of Rockbridgeite
8.BC.10
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
C : With only medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1
8 : PHOSPHATES, ARSENATES, VANADATES
B : Phosphates, etc., with additional anions, without H2O
C : With only medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1
41.9.2.1
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
9 : (AB)5(XO4)3Zq
41 : ANHYDROUS PHOSPHATES, ETC.CONTAINING HYDROXYL OR HALOGEN
9 : (AB)5(XO4)3Zq
19.12.16
19 : Phosphates
12 : Phosphates of Mn
19 : Phosphates
12 : Phosphates of Mn
Mineral Symbols
As of 2021 there are now IMA–CNMNC approved mineral symbols (abbreviations) for each mineral species, useful for tables and diagrams.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
Please only use the official IMA–CNMNC symbol. Older variants are listed for historical use only.
| Symbol | Source | Reference |
|---|---|---|
| Rkb | IMA–CNMNC | Warr, L.N. (2021). IMA–CNMNC approved mineral symbols. Mineralogical Magazine, 85(3), 291-320. doi:10.1180/mgm.2021.43 |
| Rck | The Canadian Mineralogist (2019) | The Canadian Mineralogist (2019) The Canadian Mineralogist list of symbols for rock- and ore-forming minerals (December 30, 2019). download |
Pronunciation of Rockbridgeite
Pronunciation:
| Play | Recorded by | Country |
|---|---|---|
| Jolyon Ralph | United Kingdom |
Physical Properties of Rockbridgeite
Sub-Vitreous, Resinous, Waxy, Greasy, Silky
Transparency:
Translucent, Opaque
Comment:
The cruss-sections of botryoids is radially fibrous
Colour:
Dark green, olive-green, brown, yellow-brown, greenish black, black
Comment:
Commonly exhibits colour banding. May be bronze-brown or reddish brown when oxidized.
Streak:
Gray green, pale brown
Hardness:
3½ - 4½ on Mohs scale
Tenacity:
Brittle
Cleavage:
Very Good
On {100}, excellent; on {010}, good; on {001}, fair.
On {100}, excellent; on {010}, good; on {001}, fair.
Fracture:
Irregular/Uneven
Density:
3.45 - 3.6 g/cm3 (Measured) 3.60 g/cm3 (Calculated)
Optical Data of Rockbridgeite
Type:
Biaxial (+)
RI values:
nα = 1.873 - 1.875 nβ = 1.880 nγ = 1.895 - 1.897
2V:
Measured: 45°
Birefringence:
0.022
Max. Birefringence:
δ = 0.022
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.
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.
Surface Relief:
Very High
Dispersion:
r < v, or r>v very strong
Pleochroism:
Visible
Comments:
X = Light brown to light yellow-brown
Y = Bluish green
Z = Dark bluish green
Y = Bluish green
Z = Dark bluish green
Chemistry of Rockbridgeite
Mindat Formula:
(Fe2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5
Previously given as Fe2+Fe3+4(PO4)3(OH)5.
Previously given as Fe2+Fe3+4(PO4)3(OH)5.
Element Weights:
Elements listed:
Crystallography of Rockbridgeite
Crystal System:
Orthorhombic
Class (H-M):
mmm (2/m 2/m 2/m) - Dipyramidal
Cell Parameters:
a = 13.783 Å, b = 16.805 Å, c = 5.172 Å
Ratio:
a:b:c = 0.82 : 1 : 0.308
Unit Cell V:
1,197.96 ų (Calculated from Unit Cell)
Z:
4
Morphology:
Euhedral crystals rare. Typically fibrous, elongated along [001]; compact radiating in crusts, botryoidal and drusy masses.
Comment:
Bbmm
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) |
|---|---|---|---|---|---|---|---|
| 0000198 | Rockbridgeite | Moore P B (1970) Crystal chemistry of the basic iron phosphates American Mineralogist 55 135-169 |  | 1970 | 0 | 293 |
CIF Raw Data - click here to close
X-Ray Powder Diffraction
Loading XRD data...
Data courtesy of RRUFF project at University of Arizona, used with permission.
Powder Diffraction Data:
| d-spacing | Intensity |
|---|---|
| 6.87 Å | (40) |
| 4.842 Å | (50) |
| 4.630 Å | (40) |
| 3.573 Å | (50) |
| 3.196 Å | (100) |
| 2.409 Å | (50) |
| 1.5890 Å | (50) |
Geological Environment
Paragenetic Mode(s):
| Paragenetic Mode | Earliest Age (Ga) |
|---|---|
| Near-surface Processes | |
| 22 : Hydration and low-? subsurface aqueous alteration (see also #23) | |
| Stage 4b: Highly evolved igneous rocks | >3.0 |
| 34 : Complex granite pegmatites | |
| Stage 7: Great Oxidation Event | <2.4 |
| 47a : [Near-surface hydration of prior minerals] | |
| 47c : [Carbonates, phosphates, borates, nitrates] |
Geological Setting:
Also rarely found in limonite iron ore deposits.
Type Occurrence of Rockbridgeite
Place of Conservation of Type Material:
Harvard University, Cambridge, Massachusetts, USA - #80600.
Geological Setting of Type Material:
granite pegmatite
Synonyms of Rockbridgeite
Other Language Names for Rockbridgeite
Varieties of Rockbridgeite
| Manganese-bearing rockbridgeite | Rockbridgeite bearing minor Mn of unspecified valency. May be identical to manganrockbridgeite. |
Relationship of Rockbridgeite to other Species
Member of:
Other Members of Rockbridgeite Group:
| Ferrirockbridgeite | (Fe3+0.67◻0.33)2(Fe3+)3(PO4)3(OH)4(H2O) | Orth. mmm (2/m 2/m 2/m) |
| Ferrorockbridgeite | (Fe2+,Mn2+)2(Fe3+)3(PO4)3(OH)4(H2O) | Orth. mmm (2/m 2/m 2/m) |
| Frondelite | (Mn2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5 | Orth. 2 2 2 : C2 2 21 |
| Manganrockbridgeite | Mn2+2Fe3+3(PO4)3(OH)4(H2O) | Mon. 2/m : P21/m |
| Plimerite | ZnFe3+4(PO4)3(OH)5 | Orth. mmm (2/m 2/m 2/m) |
Forms a series with:
Common Associates
Associated Minerals Based on Photo Data:
| 210 photos of Rockbridgeite associated with Strengite | FePO4 · 2H2O |
| 173 photos of Rockbridgeite associated with Hureaulite | Mn2+5(PO3OH)2(PO4)2 · 4H2O |
| 87 photos of Rockbridgeite associated with Phosphosiderite | FePO4 · 2H2O |
| 74 photos of Rockbridgeite associated with Beraunite | Fe3+6(PO4)4O(OH)4 · 6H2O |
| 74 photos of Rockbridgeite associated with Cacoxenite | Fe3+24AlO6(PO4)17(OH)12 · 75H2O |
| 73 photos of Rockbridgeite associated with Strunzite | Mn2+Fe3+2(PO4)2(OH)2 · 6H2O |
| 72 photos of Rockbridgeite associated with Kidwellite | NaFe3+9+x(PO4)6(OH)11 · 3H2O, x = 0.33 |
| 49 photos of Rockbridgeite associated with Correianevesite | Fe2+Mn2+2(PO4)2 · 3H2O |
| 48 photos of Rockbridgeite associated with Laueite | Mn2+Fe3+2(PO4)2(OH)2 · 8H2O |
| 43 photos of Rockbridgeite associated with Mitridatite | Ca2Fe3+3(PO4)3O2 · 3H2O |
Related Minerals - Strunz-mindat Grouping
| 8.BC. | Manganrockbridgeite | Mn2+2Fe3+3(PO4)3(OH)4(H2O) |
| 8.BC. | Elaliite | (Fe2+8Fe3+)(PO4)O8 |
| 8.BC. | Elkinstantonite | Fe4(PO4)2O |
| 8.BC.05 | Angelellite | Fe3+4(AsO4)2O3 |
| 8.BC.10 | Frondelite | (Mn2+0.5Fe3+0.5)2Fe3+3(PO4)3(OH)5 |
| 8.BC.10 | Ferrirockbridgeite | (Fe3+0.67◻0.33)2(Fe3+)3(PO4)3(OH)4(H2O) |
| 8.BC.10 | Ferrorockbridgeite | (Fe2+,Mn2+)2(Fe3+)3(PO4)3(OH)4(H2O) |
| 8.BC.10 | Plimerite | ZnFe3+4(PO4)3(OH)5 |
| 8.BC.15 | Aerugite | Ni8.5(AsO4)2As5+O8 |
Fluorescence of Rockbridgeite
Not fluorescent in UV
Other Information
Notes:
Soluble in HCl, but not in HNO3 or H2SO4.
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 Rockbridgeite
mindat.org URL:
https://www.mindat.org/min-3433.html
Please feel free to link to this page.
Please feel free to link to this page.
Search Engines:
External Links:
Mineral Dealers:
References for Rockbridgeite
Reference List:
Lindberg, Marie Louise (1949) Frondelite and the frondelite-rockbridgeite series. American Mineralogist, 34 (7-8) 541-549
Kingsbury, Arthur W. G. (1957) Rockbridgeite from Cornwall and Devon. Mineralogical Magazine and Journal of the Mineralogical Society, 31 (236). 429-430 doi:10.1180/minmag.1957.031.236.14
Moore, P. B. (1969) Basic Ferric Phosphates: A Crystallochemical Principle. Science, 164 (3883). 1063-1064 doi:10.1126/science.164.3883.1063
Moore, Paul B. (1970) Crystal chemistry of the basic iron phosphates. American Mineralogist, 55 (1-2) 135-169
Redhammer, Günther J., Roth, Georg, Tippelt, Gerold, Bernroider, Manfred, Lottermoser, Werner, Amthauer, Georg, Hochleitner, Rupert (2006) Manganoan rockbridgeite Fe4.32Mn0.62Zn0.06(PO4)3(OH)5: structure analysis and57Fe Mössbauer spectroscopy. Acta Crystallographica Section C Crystal Structure Communications, 62 (3) doi:10.1107/s0108270106002472
Localities for Rockbridgeite
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.
Argentina | |
| Dina (1993) |
| Demartin et al. (1997) | |
| Gay et al. (1991) +1 other reference |
| GALLISKI (1983) +1 other reference |
| Roda-Robles et al. (2012) |
Australia | |
| Birch et al. (1997) |
| Birch et al. (1997) |
| Rod Martin Collection inferred from ... |
| Harrowfield et al. (1981) |
| Peter Elliott |
| Australian Journal of Mineralogy |
| Bosworth et al. (2001) |
| Johnston et al. (1978) |
| Australian Journal of Mineralogy |
| W.D.Birch. Phosphate Minerals of ... |
| |
| Birch (2018) |
| Eagle et al. (2015) +1 other reference | |
| Eagle et al. (2015) | |
| Personally collected by Ryan Eagle in ... | |
| Birch et al. (1993) |
| Birch (1996) |
| Gole (1980) |
| Peter Downes +1 other reference |
| Hesperian Press +2 other references |
Austria | |
| Niedermayr et al. (2005) |
| Aufschluss 1972 (SB) |
Belgium | |
| Van Tassel R. (1981) +6 other references |
Bolivia | |
| Kay Robertson collection |
Brazil | |
| Queiroz (2016) | |
| Gaines et al. (1979) |
| Cassedanne et al. (1982) +1 other reference |
| sergio varvello | |
| Baijot et al. (2014) +1 other reference | |
| King (n.d.) +1 other reference | |
| King et al. (1993) | |
| fabreminerals specimen |
| A. M. I. Martins collection | |
| Cassedanne et al. (1981) |
| Atencio et al. (2004) |
| Cassedanne et al. (1999) | |
| ... |
| Sergio Varvello collection | |
| Cassedanne et al. (1973) |
| King (n.d.) |
| Witzke et al. (2000) |
| Sergio Varvello collection |
| Coelho et al. (2025) |
Chile | |
| Cesar Menor-Salvan collection +1 other reference |
Czech Republic | |
| Povondra et al. (eds.) +1 other reference |
| Sejkora et al. (2006) |
| Sejkora et al. (2006) | |
| Jirásek J. et al. (2016) |
| Škoda |
| Č +4 other references |
| Staněk (1991) +4 other references |
| Staněk (1997) | |
DR Congo | |
| Thoreau (1957) +1 other reference |
Europe | |
| Berbain et al. (2012) | |
Finland | |
| Teertstra et al. (1993) |
| Geological Survey of Finland Bulletin ... |
France | |
| perso.wanadoo.fr (2004) |
| Palache et al. (1951) |
| Palache et al. (1951) |
| Inventaire Minéralogique de la France ... |
| Bull. Soc. Franç. Minéralo. ... |
| Inventaire mineralogique de l'Ariege (Editions BRGM 1984) | |
| Bull. Soc. Franç. Minéralo. ... |
| Berbain et al. (2005) |
| Berbain et al. (2005) | |
| Berbain et al. (2012) | |
| Berbain et al. (2012) |
| Lheur et al. (2010) +1 other reference |
Germany | |
| Walenta (1992) |
| Weiß (1990) +1 other reference |
| Weiß (1990) |
| 42. (in German) +1 other reference |
| Fehr et al. (1985) |
| Palache et al. (1951) +1 other reference |
| Dill et al. (2012) | |
| Dill et al. (2008) +1 other reference | |
| Dill (2009) +3 other references |
| Weiß (1990) +1 other reference | |
| Grey et al. (2012) +2 other references | |
| Dill et al. (2015) |
| Wittern (2001) +1 other reference | |
| Weiß (1990) |
| www.vfmg-weiden.de (2001) |
| |
| DILL et al. (2009) | |
| Weber (2013) |
| in the collection of Christof Schäfer |
| Weiß (1990) |
| Blaß (2002) |
| Weiß (1990) |
| Wittern (2001) |
| Wittern (2001) +1 other reference |
| Stieglitz et al. (1987) +1 other reference |
| Weiß (1990) |
| Hucko (2010) |
| Rolf Golze +3 other references | |
| Hucko (2010) |
| Habel (2011) |
| Witzke et al. (2013) |
| Wittern (2001) |
Italy | |
| VIGNOLA et al. (2007) |
| Vignola P. et al. (2011) | |
| Vignola et al. (2011) |
Japan | |
| S. Matsubara (2000) |
| Ganko-Gakkai Koen-Yoshi (Abstracts of the Meetings of Japanese Association of Mineralogists...) | |
| Yamada (2004) | |
| Matsubara et al. (1980) |
Kazakhstan | |
| Pekov (1998) |
| Pekov (1998) |
Liberia | |
| Axelrod et al. (1952) |
Madagascar | |
| Behier (1960) |
| Behier (1960) |
| Behier (1960) |
Morocco | |
| Pavel.M. Kartashov (n.d.) +1 other reference |
| Favreau (2012) |
| Favreau (2012) | |
Namibia | |
| von Bezing (2007) |
| Förch (1998) |
| Keller et al. (1989) |
New Zealand | |
| Stott (pers. notes) |
Norway | |
| Larsen et al. (2013) +1 other reference |
Portugal | |
| Alves (n.d.) +1 other reference |
| Pedro Alves collection. Characterized ... |
| Schnorrer-Köhler et al. (1991) |
| Alves (n.d.) | |
| |
| Self-collected by Pedro Alves. |
| PROSPEG – Projecto de prospecção +1 other reference |
| Alves (n.d.) |
| |
| 4 +4 other references |
| Alves (n.d.) |
| Neves (1960) |
| |
| Alves (n.d.) | |
| Mineralien Atlas | |
| Nunes (n.d.) |
| Correia Neves (1962) |
| Alves (n.d.) |
| Identified in Rebentão Mine |
| self-find |
| Correia Neves (1966) |
Rwanda | |
| Royal Museum for Central Africa |
| Hulsbosch et al. (2019) |
| Daltry et al. (1998) |
South Africa | |
| Cairncross et al. (1995) |
Spain | |
| Roda et al. (2001) |
| Encarnación Roda-Robles (2007) |
| Roda-Robles et al. (2010) | |
| Roda-Robles et al. (2012) |
| Roda-Robles et al. (1998) |
| Garate-Olave I et al. (2014) |
| Antonio Barahona Ortiz collection |
| NÚÑEZ-GARCÍA et al. (2012) +1 other reference |
| Vérez et al. (2024) |
| Calvo Rebollar (2015) |
Sweden | |
| Bjällerud (1989) +2 other references |
| Gustafson (1989) +1 other reference |
| Swedish Museum of Natural History (Naturarv database) |
Switzerland | |
| Weiß (1989) +1 other reference |
UK | |
| Golley et al. (1995) |
| Kingsbury (1957) | |
| Weiß (1989) +1 other reference |
| [J.Russel Soc 1998:15 +2 other references |
| Kingsbury (MS1) +2 other references |
| Stanley et al. (1991) | |
| Alysson Rowan collection |
| Kingsbury (1957) |
| [Specimen in the Natural History Museum | |
| Livingstone (1980) +1 other reference |
USA | |
| Barwood et al. (1978) +1 other reference |
| Rocks & Min.: 58:57-62. | |
| Specimens collected by Jim Stoops |
| Barwood et al. (1978) +1 other reference | |
| Cook et al. (1982) | |
| Dean (1995) | |
| Dean (1995) |
| Rocks & Minerals: 70 (5) | |
| Chris Bryant. +1 other reference |
| Cook et al. (1982) |
| Howard +1 other reference |
| Smith (1988) |
| Smith (1988) |
| Rocks & Min.:64:297-298. | |
| Am Min 51:1811-1814 | |
| Smith (1988) | |
| Smith (1988) |
| Eckel et al. (1997) |
| Januzzi et al. (1976) |
| Januzzi (1976) |
| Marc V. Hurst (2012) |
| Denicourt +1 other reference |
| Marc V. Hurst (2012) |
| Marc V. Hurst (2012) | |
| Jason Smith & M.E. Ciriotti (2005) |
| King et al. (1994) |
| Thompson et al. (2000) +1 other reference |
| Mineral News (1995) +1 other reference |
| King et al. (1994) +1 other reference |
| King et al. (1994) | |
| King et al. (1994) +1 other reference | |
| King et al. (1994) +1 other reference | |
| |
| |
| Tim Blake | |
| King et al. (1994) | |
| Palache et al. (1951) |
| Harvard Mineralogical Museum |
| Silver Coin Mine. Compact Disc. Paul ... |
| Smith (2005) |
| Hurlbut (1965) +1 other reference | |
| P. Cristofono et al. (2011) |
| Smith (2005) |
| Palache et al. (1951) +2 other references |
| Palache et al. (1951) +3 other references | |
| Whitmore et al. (2004) | |
| Rocks & Min. +2 other references | |
| Thompson et al. (2022) |
| Thompson +2 other references | |
| Rocks & Min.:64:504. +1 other reference |
| Smith (2005) |
| Henderson (1980) |
| Locality description: "[...] all the ... | |
| Jeff Weismann |
| B.A. Collection. |
| Horton et al. (1981) +1 other reference |
| |
| Henderson (1980) |
| Min. Col. PA +2 other references |
| Rocks & Minerals 54:4 pp173-175 |
| Jesse Corneliusen Collection |
| Peacor (1969) +1 other reference | |
| Smith et al. (2000) |
| Rocks & Minerals: 60: 117. +1 other reference | |
| Smith et al. (2000) |
| Smith et al. (2000) |
| Rocks & Minerals: 60: 116. |
| Smith et al. (2000) | |
| Smith et al. (2000) | |
| Rocks & Minerals: 67 (6) |
| Bullock (1981) |
| Watson (1907) +1 other reference |
| Rocks & Minerals: 64: 44. +3 other references |
Quick NavTopAbout RockbridgeiteUnique IdentifiersIMA Classification Classification Mineral SymbolsPronunciation Physical Properties Optical Data Chemistry Crystallography Crystal StructureX-Ray Powder DiffractionGeological EnvironmentType Occurrence SynonymsOther LanguagesVarietiesRelationshipsCommon AssociatesStrunz-MindatFluorescence Other InformationInternet Links References Localities Locality List
Hagendorf South Pegmatite, Hagendorf, Waidhaus, Neustadt an der Waldnaab District, Upper Palatinate, Bavaria, Germany