Pickeringite Mineral Data

Pickeringite Mineral Data +

General Pickeringite Information

Chemical Formula:

MgAl2(SO4)4·22(H2O)

Composition:

Molecular Weight = 858.86 gm

Magnesium 2.83 % Mg 4.69 % MgO

Aluminum 6.28 % Al 11.87 % Al₂O₃

Hydrogen 5.16 % H 46.15 % H₂O

Sulfur 14.93 % S 37.29 % SO₃

Oxygen 70.79 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

MgAl₂(SO₄)₄·22(H₂O)

IMA Status:

Valid Species (Pre-IMA) 1844

Locality:

Link to MinDat.org Location Data.

Name Origin:

Named after J. Pickering (1777-1846).

Synonym:

Magnesia Alum

Pickeringite Image

Images:

Click Here for Larger Pickeringite Image

Pickeringite Magnesioaubertite

Comments: Aqua crystalline magnesioaubertite with white pickeringite.
Location: Grotto di Faraglione, Vulcano, Sicily, Italy. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Images:

Pickeringite

Comments: Radiating fibrous pickeringite.
Location: Patagonia, Santa Cruz County, Arizona, USA. Scale: See Photo.
© Jeff Weissman / Photographic Guide to Mineral Species

Pickeringite Crystallography

Axial Ratios:

a:b:c =0.8595:1:0.2553

Cell Dimensions:

a = 20.8, b = 24.2, c = 6.18, Z = 4; beta = 95° V = 3,098.93 Den(Calc)= 1.84

Crystal System:

Monoclinic - SphenoidalH-M Symbol (2) Space Group: P 2

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

By Intensity(I/I_o): 4.82(1), 3.51(0.9), 4.32(0.35),

Crystal Structure:

Mouse
drag1 - LMB Manipulate Structure
drag2 - RMB Resize/Rotate
Keyboard
S - Stereo Pair on/off
H - Help Screen
I - Data Info
A - Atoms On/Off
P - Polyhedra On/Off
B - Bonds On/Off
Help on Above

Quartieri S , Triscari M , Viani A , European Journal of Mineralogy , 12 (2000) p.1131-1138, Crystal structure of the hydrated sulphate pickeringite (MgAl2(SO4)4.22H2O):, X-ray powder diffraction study

Physical Properties of Pickeringite

Cleavage:

[010] Indistinct

Color:

Colorless, Yellowish white, Reddish white, Greenish white.

Density:

1.8 - 1.85, Average = 1.82

Diaphaniety:

Transparent to translucent

Fracture:

Uneven - Flat surfaces (not cleavage) fractured in an uneven pattern.

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Reniform - "Kidney like" in shape (e.g.. hematite).

Hardness:

1.5-2 - Talc-Gypsum

Luminescence:

None.

Luster:

Silky

Streak:

white

Optical Properties of Pickeringite

Gladstone-Dale:

CI meas= -0.023 (Excellent) - where the CI = (1-KPDmeas/KC)
CI calc= -0.015 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.2607,KPDmeas= 0.2628,KC= 0.2569

Optical Data:

Biaxial (-), a=1.476, b=1.48, g=1.483, bire=0.0070, 2V(Calc)=80, 2V(Meas)=60. Dispersion none.

Calculated Properties of Pickeringite

Electron Density:

r_electron=1.93 gm/cc
note: r_Pickeringite=1.84 gm/cc.

Fermion Index

Fermion Index = 0.00429
Boson Index = 0.99571

Photoelectric:

PE_Pickeringite= 1.27 barns/electron
U=PE_Pickeringite x r_electron= 2.45 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Pickeringite is Not Radioactive

Pickeringite Classification

Dana Class:

29.7.3.1 (29)Hydrated Acid and Sulfates

(29.7)where A (B)2 (XO4)4 · x(H2O)

(29.7.3)Halotrichite Group (Monoclinic with 22 H2O)

29.7.3.1 Pickeringite MgAl2(SO4)4·22(H2O) P 2 2

29.7.3.2 Halotrichite FeAl2(SO4)4·22(H2O) P 2 2

29.7.3.3 Apjohnite MnAl2(SO4)4·22(H2O) P 2₁/c 2/m

29.7.3.4 Dietrichite (Zn,Fe,Mn)Al2(SO4)4·22(H2O) P 2₁/c 2/m

29.7.3.5 Bilinite FeFe2(SO4)4·22(H2O) P 2₁/c 2/m

29.7.3.6 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4·22(H2O) Mono

29.7.3.7 Wupatkiite (Co,Mg,Ni)Al2(SO4)4·22(H2O) P 2₁/c 2/m

Strunz Class:

VI/C.12-10 VI - Sulfates,Chromates,Molybdates and Tungstates

VI/C - Water-bearing sulfates without unfamiliar anions. cations of medium and very big size

VI/C.12 - Halotrichite group, Pickeringite - Bilinite

VI/C.12-10 Pickeringite MgAl2(SO4)4·22(H2O) P 2 2

VI/C.12-12 Wupatkiite (Co,Mg,Ni)Al2(SO4)4·22(H2O) P 2₁/c 2/m

VI/C.12-20 Halotrichite FeAl2(SO4)4·22(H2O) P 2 2

VI/C.12-30 Apjohnite MnAl2(SO4)4·22(H2O) P 2₁/c 2/m

VI/C.12-40 Dietrichite (Zn,Fe,Mn)Al2(SO4)4·22(H2O) P 2₁/c 2/m

VI/C.12-50 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4·22(H2O) Mono

VI/C.12-60 Bilinite FeFe2(SO4)4·22(H2O) P 2₁/c 2/m

Other Pickeringite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(Ford32)

Search for Pickeringite using:

[ALTAVISTA] [AOL] [About.com] [All-The-Web] [HotBot] [Ixquick] [LookSmart] [MAMMA] [MSN.COM] [Netscape] [Teoma] [Wikipedia] [YAHOO]

Visit our Advertisers for Pickeringite :
AA Mineral Specimens
A-Rocks Auction
Adams Minerals
B and L Minerals
Dakota Matrix
Dan Weinrich Fine Minerals
Dan Weinrich Auctions
e-Rocks Auctions
Excalibur Minerals
Exceptional Minerals
Fabre Minerals
Greenside Minerals
John Betts Fine Minerals
Masons Minerals
Mineral News
Mineral of the Month Club
MineralsWeb Fine Minerals
Minernet.it
Rockshop.cz Kalat Fine Minerals
T G Fine Minerals
Wrights Rock Shop

Translate Pickeringite Mineral Data :

Ask about Pickeringite 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 Pickeringite Specimen Label here :

Pickeringite

MgAl2(SO4)4·22(H2O)
Dana No: 29.7.3.1 Strunz No: VI/C.12-10
Locality:

Notes: