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).

Name Pronunciation:

Pumpellyite-(Mg) + Pronunciation

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 - Prismatic H-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),

Physical Properties of Pumpellyite-(Mg)

Cleavage:

{001} Good, {100} Good

Color:

Blue green, Olive green, Brown.

Density:

3.2

Diaphaneity:

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:

Non-fluorescent.

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
Ncalc = 1.69 - 1.7

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:

Bulk Density (Electron Density)=3.18 gm/cc
note: Specific Gravity of Pumpellyite-(Mg) =3.17 gm/cc.

Fermion Index:

Fermion Index = 0.01
Boson Index = 0.99

Photoelectric:

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

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Pumpellyite-(Mg) is Not Radioactive

Pumpellyite-(Mg) Classification

Dana Class:

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

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

(58.02.02)Pumpellyite group

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

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

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

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

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

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

58.02.02.07 Pumpellyite-(Mg) Ca2MgAl2(SiO4)(Si2O7)(OH)2•(H2O) A2/m 2/m

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

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

58.02.02.10 Poppiite! Ca2(V,Fe,Mg)(V,Al)2(Si,Al)3(O,OH)14 C 2/m 2/m

58.02.02.11 Pumpellyite-(Al)! Ca2(Al,Fe,Mg)Al2(SiO4)(Si2O7)(OH,O)2•H2O A2/m 2/m

Strunz Class:

09.BG.20 09 - SILICATES (Germanates)

09.B - Sorosilicates

09.BG -Sorosilicates with mixed SiO4 and Si2O7 groups;

09.BG.20 Julgoldite-(Fe++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(OH)2•(H2O) C 2/m 2/m

09.BG.20 Julgoldite-(Fe+++) Ca2Fe(Fe,Al)2(SiO4)(Si2O7)(O,OH)2•(H2O) A2/m 2/m

09.BG.20 Pumpellyite-(Fe++) Ca2Fe(Al,Fe)2(SiO4)(Si2O7)(OH)2•(H2O) A2/m 2/m

09.BG.20 Okhotskite-(Mg)* Ca3(Mg,Mn)(Mn,Al,Fe)(SiO4)(Si2O7)(OH)2•(H2O) Mono

09.BG.20 Okhotskite-(Mn++) Ca2(Mn,Mg)(Mn,Al,Fe)Si3O10(OH)4 A2/m 2/m

09.BG.20 Pumpellyite-(Fe+++) Ca2FeAl2(SiO4)(Si2O7)(OH,O)2•(H2O) A2/m 2/m

09.BG.20 Pumpellyite-(Mg) Ca2MgAl2(SiO4)(Si2O7)(OH)2•(H2O) A2/m 2/m

09.BG.20 Pumpellyite-(Mn++) Ca2(Mn,Mg)(Al,Mn,Fe)2(SiO4)(Si2O7(OH)2•(H2O) A2/m 2/m

09.BG.20 Shuiskite Ca2(Mg,Al)(Cr,Al)2(SiO4)(Si2O7)(OH)2•(H2O) A2/m 2/m

09.BG.20 Pumpellyite-(Al)! Ca2(Al,Fe,Mg)Al2(SiO4)(Si2O7)(OH,O)2•H2O A2/m 2/m

09.BG.20 Poppiite! Ca2(V,Fe,Mg)(V,Al)2(Si,Al)3(O,OH)14 C 2/m 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 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - MinDAT
8 - Mineralienatlas (Deutsch)
9 - Online Mineral Museum
10 - QUT Mineral Atlas
11 - Ruff.Info

Search for Pumpellyite-(Mg) using:

[AOL] [Bing] [Dog Pile] [GeoScienceWorld] [HotBot] [Ixquick] [Lycos] [MAMMA] [Scirus] [Teoma] [WebCrawler] [Wikipedia] [YAHOO]

Visit our Advertisers for Pumpellyite-(Mg) :

Ask about Pumpellyite-(Mg) here :
Ask-A-Mineralogist from the Mineralogical Society of America
Mindat.org's Discussion Groups
Original Rockhounds Discussion Group
Rockhounds Discussion Group on Yahoo Groups
Mineral Discussion Forum from Fabre Minerals - also available in Español

Print or Cut-and-Paste your Pumpellyite-(Mg) Specimen Label here :

Pumpellyite-(Mg)

Ca2MgAl2(SiO4)(Si2O7)(OH)2•(H2O)
Dana No: 58.02.02.07 Strunz No: 09.BG.20
Locality:

Notes:

Dakota Matrix
Excalibur Minerals
Exceptional Minerals
Hudson Insitute
John Betts Fine Minerals
Mc Dougall Minerals
Mineral News
Rock and Mineral Shows
Weinrich Minerals, Inc.