Amesite Mineral Data

Amesite Mineral Data +

General Amesite Information

Chemical Formula:

Mg2Al(SiAl)O5(OH)4

Composition:

Molecular Weight = 278.68 gm

Magnesium 17.44 % Mg 28.92 % MgO

Aluminum 19.36 % Al 36.59 % Al₂O₃

Silicon 10.08 % Si 21.56 % SiO₂

Hydrogen 1.45 % H 12.93 % H₂O

Oxygen 51.67 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Mg₂Al₂SiO₅(OH)₄

Environment:

A product of low-grade metamorphism of Al, Mg-rich rocks.

IMA Status:

Valid Species (Pre-IMA) 1876

Locality:

At the Emery mine, Chester, Hampden Co., Massachusetts, USA. From the Lake Asbestos mine, Black Lake Link to MinDat.org Location Data.

Name Origin:

Honors James Ames, a mine owner.

Amesite Image

Images:

Amesite

Comments: White, massive amesite between quartz.
Location: Missoula, Missoula County, Montana, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Amesite Titanite

Comments: Green titanite (sphene) crystals on purple chromamesite (clinochlore?).
Location: Saranovskaya Deposit, Middle Ural Mountains, Russia. Scale: Picture size 7 cm.
© Dave Barthelmy

Amesite Crystallography

Axial Ratios:

a:b:c =0.5764:1:1.5632

Cell Dimensions:

a = 5.31, b = 9.212, c = 14.401, Z = 4; alpha = 102.11°, beta = 90.2°, gamma = 90.1° V = 688.75 Den(Calc)= 2.69

Crystal System:

Triclinic - PedialH-M Symbol (1) Space Group: C1

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

By Intensity(I/I_o): 3.52(1), 7.06(1), 1.925(0.7),

Crystal Structure:

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Anderson C S , Bailey S W , American Mineralogist , 66 (1981) p.185-195, A new cation ordering pattern in amesite-2H2

View Additional jPOWD Structure files for Amesite
[1]

Physical Properties of Amesite

Cleavage:

[001] Perfect

Color:

White, Light green.

Density:

2.77

Diaphaniety:

Transparent to translucent

Habit:

Foliated - Two dimensional platy forms.

Habit:

Micaceous - Platy texture with "flexible" plates.

Habit:

Pseudo Hexagonal - Crystals show a hexagonal outline.

Hardness:

2.5-3 - Finger Nail-Calcite

Luster:

Pearly

Streak:

pale green

Optical Properties of Amesite

Gladstone-Dale:

CI meas= 0.023 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.006 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2238,KPDmeas= 0.2173,KC= 0.2224

Optical Data:

Biaxial (+), a=1.597, b=1.597, g=1.612, bire=0.0150, 2V(Calc)=0, 2V(Meas)=0.

Calculated Properties of Amesite

Electron Density:

r_electron=2.70 gm/cc
note: r_Amesite=2.69 gm/cc.

Fermion Index

Fermion Index = 0.02239
Boson Index = 0.97761

Photoelectric:

PE_Amesite= 1.37 barns/electron
U=PE_Amesite x r_electron= 3.70 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Amesite is Not Radioactive

Amesite Classification

Dana Class:

71.1.2c.1 (71)Phyllosilicate Sheets of Six-Membered Rings

(71.1)with 1:1 layers

(71.1.2c)Serpentine group (Amesite subgroup)

71.1.2c.1 Amesite Mg2Al(SiAl)O5(OH)4 C1 1

71.1.2c.2 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m

71.1.2c.3 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2

71.1.2c.4 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m

71.1.2c.5 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 6₃ 6

71.1.2c.6 Manandonite Li2Al4[(Si2AlB)O10](OH)8 C1 1

71.1.2c.7 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 3₁m 3m

Strunz Class:

VIII/H.27-100 VIII - Silicates

VIII/H - Phyllosilicates (layered) Mica like with [Si4O10]4- and related groups

VIII/H.27 - Serpentine group

VIII/H.27-10 Antigorite (Mg,Fe)3Si2O5(OH)4 Cm m

VIII/H.27-20 Lizardite Mg3Si2O5(OH)4 P1 1

VIII/H.27-30 Clinochrysotile Mg3Si2O5(OH)4 Cc, C 2/m Mono

VIII/H.27-40 Orthochrysotile Mg3Si2O5(OH)4 Unk Ortho

VIII/H.27-50 Parachrysotile Mg3Si2O5(OH)4 Unk Ortho

VIII/H.27-55 Caryopilite (Mn,Mg,Zn,Fe)3(Si,As)2O510(OH,Cl)4 Cm or C 2/m Mono

VIII/H.27-60 Greenalite (Fe,Fe)2-3Si2O5(OH)4 Unk Mono

VIII/H.27-70 Berthierine (Fe,Fe,Al,Mg)2-3(Si,Al)2O5(OH)4 Cm m

VIII/H.27-80 Fraipontite (Zn,Al)3(Si,Al)2O5(OH)4 Cm m

VIII/H.27-90 Zinalsite Zn2AlSi2O5(OH)4·2(H2O)(?) Mono

VIII/H.27-95 Dozyite (Mg7Al2)(Si4Al2)O15(OH)12 Cm m

VIII/H.27-100 Amesite Mg2Al(SiAl)O5(OH)4 C1 1

VIII/H.27-110 Kellyite (Mn,Mg,Al)3(Si,Al)2O5(OH)4 P 6₃ 6

VIII/H.27-120 Cronstedtite Fe2Fe(SiFe)O5(OH)4 P 3₁m 3m

VIII/H.27-140 Karpinskite (Mg,Ni)2Si2O5(OH)2(?) Unk Mono

VIII/H.27-150 Nepouite Ni3Si2O5(OH)4 Ccm21 mm2

VIII/H.27-160 Pecoraite Ni3Si2O5(OH)4 C 2/m 2/m

VIII/H.27-170 Brindleyite (Ni,Mg,Fe)2Al(SiAl)O5(OH)4 C 2 2

VIII/H.27-180 Maufite (Mg,Ni)Al4Si3O13·4(H2O)(?) Mono ? Mono

VIII/H.27-190 Carlosturanite (Mg,Fe,Ti,Mn)21(Si,Al)12O28(OH)34 Cm m

Other Amesite Information

References:

NAME( AntBidBlaNic2) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

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Amesite

Mg2Al(SiAl)O5(OH)4
Dana No: 71.1.2c.1 Strunz No: VIII/H.27-100
Locality:

Notes: