Protoanthophyllite Mineral Data

General Protoanthophyllite Information

Chemical Formula:

(Mg,Fe)7Si8O22(OH)2

Composition:

Molecular Weight = 801.60 gm

Sodium 0.17 % Na 0.23 % Na₂O

Magnesium 19.13 % Mg 31.73 % MgO

Manganese 0.07 % Mn 0.09 % MnO

Aluminum 0.47 % Al 0.89 % Al₂O₃

Iron 4.25 % Fe 5.47 % FeO

Silicon 27.68 % Si 59.21 % SiO₂

Nickel 0.07 % Ni 0.09 % NiO

Hydrogen 0.25 % H 2.25 % H₂O

Oxygen 47.90 % O

______ ______

100.00 % 99.96 % = TOTAL OXIDE

Empirical Formula:

Mg_6.31Fe²⁺_0.61Na_0.06Mn²⁺_0.01Ni_0.01Si_7.9Al_0.14O₂₂(OH)₂

Environment:

Contact metamorphosed Takase ultramafic complex (serpentinites).

IMA Status:

Approved IMA 2003 (Dana # Added)

Locality:

Drill-core sample from the waste dump of the abandoned Takase chromite mine, Okayama Prefecture, Japan. Link to MinDat.org Location Data.

Name Origin:

Named as the proto-type analog of anthophyllite. The prefix proto refers to a half-rotation about the b axis between successive layers of octahedra.

Synonym:

IMA2001-065

Protoanthophyllite Image

Images:

Protoanthophyllite

Comments: Drill core showing white acicular crystalline aggregates of protoanthophyllite in matrix with a close up image on the right..
Location: Drill-core sample from the waste dump of the abandoned Takase chromite mine, Okayama Prefecture, Japan. Scale: Core size 3 cm.
© American Mineralogist

Protoanthophyllite Crystallography

Axial Ratios:

a:b:c =0.5217:1:0.2962

Cell Dimensions:

a = 9.3553, b = 17.9308, c = 5.3117, Z = 2; V = 891.03 Den(Calc)= 2.99

Crystal System:

Orthorhombic - Dipyramidal H-M Symbol (2/m 2/m 2/m) Space Group: Pnmn

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

By Intensity(I/I_o): 3.66(1)(131), 3.08(0.81)(310), 8.32(0.71)(110),2.51(0.57)(202), 2.56(0.49)(102), 3.27(0.49)(221),

Physical Properties of Protoanthophyllite

Cleavage:

{110} Perfect, {110} Perfect

Color:

Colorless, White.

Diaphaneity:

Transparent

Fracture:

Brittle - Uneven - Very brittle fracture producing uneven fragments.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

6 - Orthoclase

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Protoanthophyllite

Gladstone-Dale:

CI calc= 0.022 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2026,KC= 0.2072
Ncalc = 1.62

Optical Data:

Biaxial (-), a=1.593, b=1.609, g=1.615, bire=0.0220

Calculated Properties of Protoanthophyllite

Electron Density:

Bulk Density (Electron Density)=2.98 gm/cc
note: Specific Gravity of Protoanthophyllite =2.99 gm/cc.

Fermion Index:

Fermion Index = 0.03
Boson Index = 0.97

Photoelectric:

PE_{Protoanthophyllite}= 2.80 barns/electron
U=PE_{Protoanthophyllite} x rElectron Density= 8.33 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Protoanthophyllite is Not Radioactive

Protoanthophyllite Classification

Dana Class:

66.01.02.02a (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.01)with P=2 amphibole configuration

(66.01.02)Dana Group

66.01.02.01 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.02 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.02a Protoanthophyllite! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

66.01.02.03 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.03a Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

66.01.02.03b Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

66.01.02.04 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.04a Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.05 Magnesiogedrite? (Mg,Fe)5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.06 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.07 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.07a Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.08 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.09 Magnesioholmquistite Li2(Mg,Fe)3Al2Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.10 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

66.01.02.11 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

Strunz Class:

09.DE.05 09 - SILICATES (Germanates)

09.D - Inosilicates* Structural terminology according to Liebau (1985)

09.DE -Inosilicates with 2-periodic double chains, Si4O11; amphibole family

09.DE.05 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Cummingtonite []Mg7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Clinoferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Grunerite []Fe7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Magnesiocummingtonite (Mg,Fe)7Si8O22(OH)2 C 2/m 2/m

09.DE.05 Manganogrunerite []Mn2Fe5Si8O22(OH) C 2/m 2/m

09.DE.05 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

09.DE.05 Permanganogrunerite! []Mn4(Fe)3(Si8O22)(OH)2 C 2/m 2/m

09.DE.05 Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Fluoro-sodic-pedrizite! NaLi2(Mg2Al2Li)S5Si8O22F2 C 2/m 2/m

09.DE.05 Sodic-ferri-ferropedrizite! NaLi2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Manganocummingtonite Na(Na,Mn)2(Mg4,Fe)5Si8O22(OH)2 C 2/m 2/m

09.DE.05 Protoanthophyllite! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

09.DE.05 Ferri-clinoferroholmquistite! []Li2(Fe2Fe3)Si8O22(OH)2 C 2/m 2/m

09.DE.05 Sodic-ferripedrizite! Na(LiNa)(Fe2Mg2Li)Si8O22(OH,F)2 C 2/m 2/m

09.DE.05 Ferripedrizite! NaLi2(Fe2Mg2Li)Si8O22(OH)2 C 2/m 2/m

Other Protoanthophyllite Information

References:

NAME( AmMin, v 88, p 1718) PHYS. PROP.(AmMin, v 88, p 1718) OPTIC PROP.(AmMin, v 88, p 1718)

See Also:

Links to other databases for Protoanthophyllite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - GeoScienceWorld
4 - Google Images
5 - Google Scholar
6 - MinDAT
7 - Mineralienatlas (Deutsch)
8 - Online Mineral Museum
9 - QUT Mineral Atlas
10 - Ruff.Info

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Print or Cut-and-Paste your Protoanthophyllite Specimen Label here :

Protoanthophyllite

(Mg,Fe)7Si8O22(OH)2
Dana No: 66.01.02.02a Strunz No: 09.DE.05
Locality:

Notes:

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