Pumpellyite-(Mg) Mineral Data

Pumpellyite-(Mg) Mineral Data +

General Pumpellyite-(Mg) Information

Chemical Formula:

Ca2MgAl2(SiO4)(Si2O7)(OH)2·(H2O)

Composition:

Molecular Weight = 470.70 gm

Calcium 17.03 % Ca 23.83 % CaO

Magnesium 5.16 % Mg 8.56 % MgO

Aluminum 11.46 % Al 21.66 % Al₂O₃

Silicon 17.90 % Si 38.29 % SiO₂

Hydrogen 0.86 % H 7.65 % H₂O

Oxygen 47.59 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Ca₂MgAl₂(SiO₄)(Si₂O₇)(OH)₂·(H₂O)

Environment:

Meta-basalt or gabbroic rocks.

IMA Status:

Valid Species (Pre-IMA) 1925

Locality:

Calumet mine, Houghton County, Keweenaw Peninisula, Michigan, USA. Link to MinDat.org Location Data.

Name Origin:

Named after the American geologist, R. Pumpelly (1837-1923).

Synonym:

Pumpellyite

Pumpellyite-(Mg) Image

Images:

Pumpellyite-(Mg)

Comments: Greenish, flattened, prismatic crystals of pumpellyite-(Mg) ? to 3mm.
Location: Deere Island, Novato, Marin Co., California, USA. Scale: Picture size 5 mm.
© Tom Loomis / Dakota Matrix

Pumpellyite-(Mg) Crystallography

Axial Ratios:

a:b:c =1.4939:1:3.2384

Cell Dimensions:

a = 8.82, b = 5.904, c = 19.12, Z = 4; beta = 97.4° V = 987.35 Den(Calc)= 3.17

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: A2/m

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

By Intensity(I/I_o): 2.9(1), 2.74(0.5), 3.79(0.5),

Crystal Structure:

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Artioli G , Geiger C A , Physics and Chemistry of Minerals , 20 (1994) p.443-453, The crystal chemistry of pumpellyite: An X-ray Rietveld, refinement and 57Fe Mossbauer study, Note: sample HR, Locality: Hicks Ranch, California

View Additional jPOWD Structure files for Pumpellyite-(Mg)
[1] [2]

Physical Properties of Pumpellyite-(Mg)

Cleavage:

[001] Good, [100] Good

Color:

Blue green, Olive green, Brown.

Density:

3.2

Diaphaniety:

Translucent

Fracture:

Sub Conchoidal - Fractures developed in brittle materials characterized by semi-curving surfaces.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Massive - Lamellar - Distinctly foliated fine-grained forms.

Habit:

Spherical - Spherical, rounded aggregates.

Hardness:

5.5 - Knife Blade

Luminescence:

None.

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Pumpellyite-(Mg)

Gladstone-Dale:

CI meas= 0.007 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.002 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2182,KPDmeas= 0.2161,KC= 0.2177

Optical Data:

Biaxial (+), a=1.67-1.698, b=1.672-1.706, g=1.684-1.72, bire=0.0140-0.0220, 2V(Calc)=46-76, 2V(Meas)=10-50. Dispersion relatively strong.

Calculated Properties of Pumpellyite-(Mg)

Electron Density:

r_electron=3.18 gm/cc
note: r_{Pumpellyite-(Mg)}=3.17 gm/cc.

Fermion Index

Fermion Index = 0.01398
Boson Index = 0.98602

Photoelectric:

PE_{Pumpellyite-(Mg)}= 3.23 barns/electron
U=PE_{Pumpellyite-(Mg)} x r_electron= 10.27 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pumpellyite-(Mg) is Not Radioactive

Pumpellyite-(Mg) Classification

Dana Class:

58.2.2.7 (58)Sorosilicate Insular, Mixed, Single, and Larger Tetrahedral Groups

(58.2)with cations in [6] and higher coordination; single and double groups (n=1,2)

(58.2.2)Pumpellyite group

58.2.2.1 Julgoldite-(Fe++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(OH)2·(H2O) C 2/m 2/m

58.2.2.2 Julgoldite-(Fe+++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(O,OH)2·(H2O) A2/m 2/m

58.2.2.3 Okhotskite-(Mg)* Ca3(Mg,Mn)(Mn,Al,Fe)(SiO4)(Si2O7)(OH)2·(H2O) Mono

58.2.2.4 Okhotskite-(Mn++) Ca2(Mn,Mg)(Mn,Al,Fe)Si3O10(OH)4 A2/m 2/m

58.2.2.5 Pumpellyite-(Fe++) Ca2Fe(Al,Fe)2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

58.2.2.6 Pumpellyite-(Fe+++) Ca2FeAl2(SiO4)(Si2O7)(OH,O)2·(H2O) A2/m 2/m

58.2.2.7 Pumpellyite-(Mg) Ca2MgAl2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

58.2.2.8 Pumpellyite-(Mn++) Ca2(Mn,Mg)(Al,Mn,Fe)2(SiO4)(Si2O7(OH)2·(H2O) A2/m 2/m

58.2.2.9 Shuiskite Ca2(Mg,Al)(Cr,Al)2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

Strunz Class:

VIII/C.24-30 VIII - Silicates

VIII/C - Sorosilicates, mixed structure with [SiO4]2- "inseln" and [Si2O7]6- groups

VIII/C.24 - Pumpellyite group

VIII/C.24-10 Macfallite Ca2(Mn,Al)3(SiO4)(Si2O7)(OH)3 P 2₁/m 2/m

VIII/C.24-20 Sursassite Mn2Al3(SiO4)(Si2O7)(OH)3 P 2₁/m 2/m

VIII/C.24-30 Pumpellyite-(Mg) Ca2MgAl2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

VIII/C.24-40 Pumpellyite-(Fe++) Ca2Fe(Al,Fe)2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

VIII/C.24-42 Pumpellyite-(Fe+++) Ca2FeAl2(SiO4)(Si2O7)(OH,O)2·(H2O) A2/m 2/m

VIII/C.24-50 Pumpellyite-(Mn++) Ca2(Mn,Mg)(Al,Mn,Fe)2(SiO4)(Si2O7(OH)2·(H2O) A2/m 2/m

VIII/C.24-60 Julgoldite-(Fe++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(OH)2·(H2O) C 2/m 2/m

VIII/C.24-61 Julgoldite-(Fe+++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(O,OH)2·(H2O) A2/m 2/m

VIII/C.24-70 Shuiskite Ca2(Mg,Al)(Cr,Al)2(SiO4)(Si2O7)(OH)2·(H2O) A2/m 2/m

VIII/C.24-80 Okhotskite-(Mg)* Ca3(Mg,Mn)(Mn,Al,Fe)(SiO4)(Si2O7)(OH)2·(H2O) Mono

VIII/C.24-80* Okhotskite-(Mn++) Ca2(Mn,Mg)(Mn,Al,Fe)Si3O10(OH)4 A2/m 2/m

VIII/C.24-90 Samfowlerite Ca14Mn3Zn2(Be,Zn)2Be6(SiO4)6(Si2O7)4(OH,F)6 P 2₁/c 2/m

Other Pumpellyite-(Mg) Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Dana8) OPTIC PROP.(Dana8)

See Also:

Links to other databases for Pumpellyite-(Mg) :
1 -Am. Min. Crystal Structure Database 2 -Athena 3 - Franklin Minerals(Dunn) 4 -Google Images 5 -Google Scholar 6 -Handbook of Mineralogy (MinSocAm) 7 -MinDAT 8 -MinMax(Deutsch) 9 -MinMax(English) 10 -Mineralienatlas (Deutsch) 11 -QUT Mineral Atlas

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Pumpellyite-(Mg)

Ca2MgAl2(SiO4)(Si2O7)(OH)2·(H2O)
Dana No: 58.2.2.7 Strunz No: VIII/C.24-30
Locality:

Notes: