Rockbridgeite Mineral Data
General Rockbridgeite Information
Chemical Formula:
(Fe++,Mn)Fe+++4(PO4)3(OH)5
Composition:
Molecular Weight = 648.96 gm
Manganese 2.12 % Mn 2.73 % MnO
Iron 40.88 % Fe 8.30 % FeO / 49.21 % Fe2 O3
Phosphorus 14.32 % P 32.81 % P2 O5
Hydrogen 0.78 % H 6.94 % H2 O
Oxygen 41.91 % O
______ ______
100.00 % 100.00 % = TOTAL OXIDE
Empirical Formula:
Fe2+ 0.75 Mn2+ 0.25 Fe3+ 4 (PO4 )3 (OH)5
Environment:
Alteration product of triphylite and other manganese phosphates. Forms a series with frondelite.
IMA Status:
Valid Species (Pre-IMA) 1949
Locality:
South Mountain, near Midvale, Rockbridge County, Virginia, USA. Link to MinDat.org Location Data.
Name Origin:
Named for the locality.
Name Pronunciation:
Rockbridgeite + Pronunciation
Synonym:
Andrewsite
ICSD 34829
PDF 22-356
Rockbridgeite Image
Images:
Images:
Images:
Images:
Images:
Lindbergite Rockbridgeite
Comments: Rare organic mineral - lindbergite (Mn dihydrate oxalate) in white patches on rockbridgeite matrix.
Location: Boca Rica mine, Sapucaia do Norte, Gilileia, Minas Gerais, Brazil.
Scale: Spot size 1 mm.
© Tom Loomis / Dakota Matrix
Rockbridgeite Crystallography
Axial Ratios:
a:b:c =0.8201:1:0.3077
Cell Dimensions:
a = 13.783, b = 16.805, c = 5.172, Z = 4; V = 1,197.96 Den(Calc)= 3.60
Crystal System:
Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Bbmm
X Ray Diffraction:
By Intensity(I/Io ): 3.196(1), 3.573(0.5), 4.842(0.5),
Physical Properties of Rockbridgeite
Cleavage:
{100} Perfect, {010} Distinct, {001} Distinct
Color:
Green, Dark olive green, Black, Brownish green, Reddish brown.
Density:
3.3 - 3.49, Average = 3.39
Diaphaneity:
Subtranslucent
Fracture:
Brittle - Uneven - Very brittle fracture producing uneven fragments.
Hardness:
4.5 - Between Fluorite and Apatite
Luster:
Vitreous - Dull
Streak:
greenish gray
Optical Properties of Rockbridgeite
Gladstone-Dale:
CI meas = -0.003 (Superior) - where the CI = (1-KPDmeas /KC ) CI calc = 0.054 (Good) - where the CI = (1-KPDcalc /KC )
KPDcalc = 0.2456,KPDmeas = 0.2604,KC = 0.2596 Ncalc = 1.86 - 1.93
Optical Data:
Biaxial (+), a=1.875, b=1.88, g=1.897, bire=0.0220
Calculated Properties of Rockbridgeite
Electron Density:
Bulk Density (Electron Density)=3.30 gm/cc note: Specific Gravity of Rockbridgeite =3.40 gm/cc.
Fermion Index:
Fermion Index = 0.008868215 Boson Index = 0.991131785
Photoelectric:
PERockbridgeite = 13.47 barns/electronU=PERockbridgeite x r Electron Density= 44.52 barns/cc.
Radioactivity:
GRapi = 0 (Gamma Ray American Petroleum Institute Units) Rockbridgeite is Not Radioactive
Rockbridgeite Classification
Dana Class:
41.09.02.01 (41) Anhydrous Phosphates, etc. Containing Hydroxyl or Halogen
(41.09) where (A B)5 (XO4)3 Zq
(41.09.02) Rockbridgeite Group
41.09.02.01 Rockbridgeite (Fe,Mn)Fe4(PO4)3(OH)5 Bbmm 2/m 2/m 2/m
41.09.02.02 Frondelite MnFe4(PO4)3(OH)5 Bbmm 2/m 2/m 2/m
41.09.02.03 Plimerite ! ZnFe4(PO4)3(OH)5 C mcm 2/m 2/m 2/m
Strunz Class:
08.BC.10 08 - PHOSPHATES, ARSENATES, VANADATES
08.B - Phosphates, etc. with Additional Anions, without H2O
08.BC -With only medium-sized cations, (OH, etc.):RO4 > 1:1 and < 2:1
08.BC.10 Frondelite MnFe4(PO4)3(OH)5 Bbmm 2/m 2/m 2/m
08.BC.10 Rockbridgeite (Fe,Mn)Fe4(PO4)3(OH)5 Bbmm 2/m 2/m 2/m
08.BC.10 Plimerite ! ZnFe4(PO4)3(OH)5 C mcm 2/m 2/m 2/m
Other Rockbridgeite Information
References:
NAME( Dana8) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Enc. of Minerals,2nd ed.,1990)
See Also:
Links to other databases for Rockbridgeite :
1 - Am. Min. Crystal Structure Database
2 - Amethyst Galleries' Mineral Gallery
3 - Athena
4 - CalTech Mineral Spectroscopy
5 - EUROmin Project
6 - Ecole des Mines de Paris
7 - GeoScienceWorld
8 - Google Images
9 - Google Scholar
10 - Handbook of Mineralogy (MinSocAm)
11 - Handbook of Mineralogy (UofA)
12 - MinDAT
13 - Mineralienatlas (Deutsch)
14 - Online Mineral Museum
15 - QUT Mineral Atlas
16 - Ruff.Info
17 - WWW-MINCRYST
Search for Rockbridgeite using:
[AOL ]
[Bing ]
[Dog Pile ]
[GeoScienceWorld ]
[HotBot ]
[Ixquick ]
[Lycos ]
[MAMMA ]
[Scirus ]
[Teoma ]
[WebCrawler ]
[Wikipedia ]
[YAHOO ]
Visit our Advertisers for Rockbridgeite :
Ask about Rockbridgeite here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in
Espa�ol
Print or Cut-and-Paste your Rockbridgeite Specimen Label here :
Rockbridgeite
(Fe++,Mn)Fe+++4(PO4)3(OH)5
Dana No: 41.09.02.01 Strunz No: 08.BC.10
Locality:
Notes:
Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.