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 % Fe₂O₃

Phosphorus 14.32 % P 32.81 % P₂O₅

Hydrogen 0.78 % H 6.94 % H₂O

Oxygen 41.91 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Fe²⁺_0.75Mn²⁺_0.25Fe³⁺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:

Rockbridgeite

Comments: Black cruciform twins of rockbridgeite on siderite.
Location: Big Chief mine, Keystone, Pennington County, South Dakota, USA. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Stewartite Rockbridgeite

Comments: Pointed, brownish yellow stewartite crystals on massive, dark rockbridgeite.
Location: Hagendorf, Bavaria, Germany. Scale: Not Given.
© Lou Perloff / Photo Atlas of Minerals

Images:

Wilhelmvierlingite Rockbridgeite

Comments: Yellow brown crystals wilhelmvierlingite with black rockbridgeite.
Location: Hagendorf South Pegmatite (Cornelia Mine; Hagendorf South Open Cut), Waidhaus, Vohenstrauß, Oberpfalz, Bavaria, Germany. Scale: Picture size 5 mm.
© Thomas Witzke / Abraxas-Verlag

Images:

Tinsleyite Phosphosiderite Rockbridgeite

Comments: Violet botryoidal tinsleyite on bluish-purple botryoidal phosphosiderite on dark, massive rockbridgeite.
Location: Bendada, Guarda, Portugal. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

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

$Help on X Ray Diffraction:$ X Ray Diffraction:

By Intensity(I/I_o): 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:

PE_{Rockbridgeite}= 13.47 barns/electron
U=PE_{Rockbridgeite} x rElectron 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

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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:

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