Krohnkite Mineral Data

General Krohnkite Information

Chemical Formula:

Na2Cu(SO4)2•2(H2O)

Composition:

Molecular Weight = 337.68 gm

Sodium 13.62 % Na 18.35 % Na₂O

Copper 18.82 % Cu 21.19 % Cu₂O

Hydrogen 1.19 % H 10.67 % H₂O

Sulfur 18.99 % S 47.42 % SO₃

Oxygen 47.38 % O

______ ______

100.00 % 97.63 % = TOTAL OXIDE

Empirical Formula:

Na₂Cu(SO₄)₂•2(H₂O)

Environment:

Secondary mineral in copper-bearing sulfide deposits.

IMA Status:

Valid Species (Pre-IMA) 1876

Locality:

Chuquicamata, Calama, Antofagásta Province, Chile. Link to MinDat.org Location Data.

Name Origin:

Named after B. Kroehnke, who was the first person to analyze it.

Synonym:

Kroehnkite

Krohnkite Image

Images:

Krohnkite Natrochalcite

Comments: Royal blue krÃ¶hnkite and green natrochalcite.
Location: Chiquicamata, Chile. Scale: 3.5 x 2 cm.
© John Veevaert

Krohnkite Crystallography

Axial Ratios:

a:b:c =0.4584:1:0.4356

Cell Dimensions:

a = 5.8, b = 12.651, c = 5.512, Z = 2; beta = 108.45° V = 383.66 Den(Calc)= 2.92

Crystal System:

Monoclinic - PrismaticH-M Symbol (2/m) Space Group: P 2₁/c

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

By Intensity(I/I_o): 6.32(1), 3.28(0.75), 2.928(0.65),

Forms:

Mouse
Dbl Clk - Start-Stop Rotation
RMB - Cycle Display Modes
Drag1 - Manipulate Crystal
Drag2 - Resize
Keyboard
S - Stereo
I - Indicies
<space> - Start-Stop Rotation
F - Fit to Screen
M - Menu
Help on Above

Forms: ( 1 1 1) ( 0 1 0) ( 0 1 1) ( 1 3 0) ( 1 3 1) ( 1 2 0) ( 0 1 2) ( 1 0 0) ( 1 1 0)

Warning: this large pop-up is very compute intensive and may not work well with some computers.

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

Hawthorne F C , Ferguson R B , Acta Crystallographica, Section B , 31 (1975) p.1753-1755, Refinement of the crystal structure of krohnkite, Locality: Chuquicamata, Chile

Physical Properties of Krohnkite

Cleavage:

{010} Perfect, {011} Good

Color:

Blue, Dark sky blue, Greenish blue, Yellowish green.

Density:

2.06 - 2.9, Average = 2.48

Diaphaneity:

Transparent to Translucent

Fracture:

Conchoidal - Fractures developed in brittle materials characterized by smoothly curving surfaces, (e.g. quartz).

Habit:

Encrustations - Forms crust-like aggregates on matrix.

Habit:

Fibrous - Crystals made up of fibers.

Habit:

Massive - Fibrous - Distinctly fibrous fine-grained forms.

Hardness:

2.5-3 - Finger Nail-Calcite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Krohnkite

Gladstone-Dale:

CI meas= -0.132 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.039 (Excellent) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1967,KPDmeas= 0.2316,KC= 0.2047
Ncalc = 1.42 - 1.6

Optical Data:

Biaxial (-), a=1.544, b=1.578, g=1.601, bire=0.0570, 2V(Calc)=76, 2V(Meas)=78.7.

Calculated Properties of Krohnkite

Electron Density:

Bulk Density (Electron Density)=2.89 gm/cc
note: Specific Gravity of Krohnkite =2.92 gm/cc.

Fermion Index:

Fermion Index = 0.0016535964
Boson Index = 0.9983464036

Photoelectric:

PE_Krohnkite= 9.42 barns/electron
U=PE_Krohnkite x rElectron Density= 27.20 barns/cc.

Radioactivity:

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

Krohnkite Classification

Dana Class:

29.03.02.01 (29)Hydrated Acid and Sulfates

(29.03)where (A+)2 B (XO4)2 · x(H2O)

(29.03.02)Dana Group

29.03.02.01 Krohnkite Na2Cu(SO4)2•2(H2O) P 2₁/c 2/m

Strunz Class:

07.CC.30 07 - SULFATES (SELENATES, TELLURATES)

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

07.CC -With medium-sized and large cations

07.CC.30 Krohnkite Na2Cu(SO4)2•2(H2O) P 2₁/c 2/m

Other Krohnkite Information

References:

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

See Also:

Links to other databases for Krohnkite :
1 - Am. Min. Crystal Structure Database
2 - Athena
3 - EUROmin Project
4 - GeoScienceWorld
5 - Google Images
6 - Google Scholar
7 - Handbook of Mineralogy (MinSocAm)
8 - Handbook of Mineralogy (UofA)
9 - MinDAT
10 - Mineralienatlas (Deutsch)
11 - Online Mineral Museum
12 - QUT Mineral Atlas
13 - Ruff.Info
14 - WWW-MINCRYST

Search for Krohnkite using:

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

Visit our Advertisers for Krohnkite :

A Bijoux Google Search for Krohnkite
Adam's Minerals Google Search for Krohnkite
Cape Minerals Google Search for Krohnkite
Dakota Matrix Minerals Google Search for Krohnkite
Excalibur Mineral Corp. Google Search for Krohnkite
Exceptional Minerals Google Search for Krohnkite
John Betts Fine Minerals Search for Krohnkite
McDougall Minerals Google Search for Krohnkite
Mineral News Website Link
Rock and Mineral Shows Google Search for Krohnkite
Weinrich Minerals, Inc. Google Search for Krohnkite

Ask about Krohnkite 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 Krohnkite Specimen Label here :

Krohnkite

Na2Cu(SO4)2•2(H2O)
Dana No: 29.03.02.01 Strunz No: 07.CC.30
Locality:

Notes: