Protoanthophyllite Mineral Data

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 - DipyramidalH-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),

Crystal Structure:

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Konishi H , Groy T L , Dodony I , Miyawaki R , Matsubara S , Buseck P R , American Mineralogist , 88 (2003) p.1718-1723, Crystal structure of protoanthophyllite: A new mineral from the takese ultramafic, complex, Japan

Physical Properties of Protoanthophyllite

Cleavage:

[110] Perfect, [110] Perfect

Color:

Colorless, White.

Diaphaniety:

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

Optical Data:

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

Calculated Properties of Protoanthophyllite

Electron Density:

r_electron=2.98 gm/cc
note: r_{Protoanthophyllite}=2.99 gm/cc.

Fermion Index

Fermion Index = 0.03319
Boson Index = 0.96681

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Protoanthophyllite is Not Radioactive

Protoanthophyllite Classification

Dana Class:

66.1.2.2a (66)Inosilicate Double-Width Unbranched Chains, W=2

(66.1)Dana Type

(66.1.2)Group 1, the Mg-Fe-Mn-Li amphiboles (Orthorhombic)

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

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

66.1.2.2a Protoanthophyllite ! (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

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

66.1.2.3a Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

66.1.2.3b Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

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

66.1.2.4a Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

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

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

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

66.1.2.7a Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

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

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

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

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

66.1.2.12 IMA2004-030! []Li2(Fe3Al2)S5(Si8O22)(OH)2 P nma 2/m 2/m 2/m

Strunz Class:

VIII/F.12-140* VIII - Silicates

VIII/F - Inosilicates (chain and band) double chains [Si4O11]6-, Orthorhombic Amphiboles

VIII/F.12 - Amphibole group, Magnesioholmquistite - Ferrogedrite series

VIII/F.12-10 Magnesioholmquistite Li2(Mg,Fe)3Al2Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-20 Holmquistite [](Li2Mg3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-30 Ferroholmquistite [](Li2Fe3Al2)Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-40 Sodicanthophyllite NaMg7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-45 Sodic-ferro-anthophyllite! NaFe7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-50 Magnesioanthophyllite? (Mg,Fe)7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-60 Anthophyllite []Mg7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-70 Ferro-anthophyllite []Fe7Si8O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-75 Sodic-ferrogedrite! NaFe6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-80 Sodicgedrite NaMg6AlSi6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-90 Magnesiogedrite? (Mg,Fe)5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-100 Gedrite []Mg5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-110 Ferrogedrite []Fe5Al2Si6Al2O22(OH)2 P nma 2/m 2/m 2/m

VIII/F.12-130 Protoferro-anthophyllite! (Fe,Mn)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 2/m 2/m

VIII/F.12-140* Protoanthophyllite (Mg,Fe)7Si8O22(OH)2 Pnmn 2/m 2/m 2/m

VIII/F.12-140 Protomangano-ferro-anthophyllite! (Mn,Fe)2(Fe,Mg)5(Si4O11)2(OH)2 Pnmn 2/m 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 -Google Images 4 -Google Scholar 5 -MinDAT 6 -MinMax(Deutsch) 7 -MinMax(English) 8 -Mineralienatlas (Deutsch) 9 -QUT Mineral Atlas

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

Protoanthophyllite

(Mg,Fe)7Si8O22(OH)2
Dana No: 66.1.2.2a Strunz No: VIII/F.12-140*
Locality:

Notes: