Pickeringite Mineral Data

[How the Club Works] [Memberships - Junior, Deluxe , and Platinum] [FAQ] [Past Minerals]
Join the Club - Junior, Deluxe and Platinum Memberships Available
High Quality Minerals Sent to Your Home or School Each Month
Mineral of the Month Club - An Inexpensive Way to Enjoy Minerals

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).

Name Pronunciation:

Pickeringite + Pronunciation

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

Diaphaneity:

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:

Non-fluorescent.

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
Ncalc = 1.46 - 1.48

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:

Bulk Density (Electron Density)=1.93 gm/cc
note: Specific Gravity of Pickeringite =1.84 gm/cc.

Fermion Index:

Fermion Index = 0.0042975192
Boson Index = 0.9957024808

Photoelectric:

PE_Pickeringite= 1.27 barns/electron
U=PE_Pickeringite x rElectron Density= 2.45 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)
Pickeringite is Not Radioactive

Pickeringite Classification

Dana Class:

29.07.03.01 (29)Hydrated Acid and Sulfates

(29.07)where A (B)2 (XO4)4 · x(H2O)

(29.07.03)Halotrichite Group (Monoclinic with 22 H2O)

29.07.03.01 Pickeringite MgAl2(SO4)4•22(H2O) P 2 2

29.07.03.02 Halotrichite FeAl2(SO4)4•22(H2O) P 2 2

29.07.03.03 Apjohnite MnAl2(SO4)4•22(H2O) P 2₁/c 2/m

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

29.07.03.05 Bilinite FeFe2(SO4)4•22(H2O) P 2₁/c 2/m

29.07.03.06 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4•22(H2O) Mono

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

Strunz Class:

07.CB.85 07 - SULFATES (SELENATES, TELLURATES)

07.C - Sulfates (selenates, etc.) without Additional Anions, with H2O

07.CB -With only medium-sized cations

07.CB.85 Bilinite FeFe2(SO4)4•22(H2O) P 2₁/c 2/m

07.CB.85 Apjohnite MnAl2(SO4)4•22(H2O) P 2₁/c 2/m

07.CB.85 Dietrichite (Zn,Fe,Mn)Al2(SO4)4•22(H2O) P 2₁/c 2/m

07.CB.85 Halotrichite FeAl2(SO4)4•22(H2O) P 2 2

07.CB.85 Pickeringite MgAl2(SO4)4•22(H2O) P 2 2

07.CB.85 Redingtonite (Fe,Mg,Ni)(Cr,Al)2(SO4)4•22(H2O) Mono

07.CB.85 Wupatkiite (Co,Mg,Ni)Al2(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)

See Also:

Links to other databases for Pickeringite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - Ecole des Mines de Paris
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - MinMax(Deutsch)
11 - MinMax(English)
12 - Mineralienatlas (Deutsch)
13 - QUT Mineral Atlas
14 - Ruff.Info
15 - WWW-MINCRYST

Search for Pickeringite using:

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

Visit our Advertisers for Pickeringite :

AA Mineral Specimens

B & L Fine Minerals

Crystalarium.com

Dan Weinrich Fine Minerals

Dan Weinrich Auctions

Dakota Matrix

Desert Winds Gems and Minerals

John Betts Fine Minerals

Mason's Minerals

Mineral News

Mineral of the Month Club

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: 29.07.03.01 Strunz No: 07.CB.85
Locality:

Notes: