Legrandite Mineral Data

Legrandite Mineral Data +

General Legrandite Information

Chemical Formula:

Zn2(AsO4)(OH)·(H2O)

Composition:

Molecular Weight = 304.72 gm

Zinc 42.92 % Zn 53.42 % ZnO

Arsenic 24.59 % As 37.71 % As₂O₅

Hydrogen 0.99 % H 8.87 % H₂O

Oxygen 31.50 % O

______ ______

100.00 % 100.00 % = TOTAL OXIDE

Empirical Formula:

Zn₂(AsO₄)(OH)·(H₂O)

Environment:

Secondary mineral in zinc orebodies.

IMA Status:

Valid Species (Pre-IMA) 1932

Locality:

Ojuela mine near Mapimi, Durango. Link to MinDat.org Location Data.

Name Origin:

Named after the Belgian mining engineer, Legrande.

Synonym:

ICSD 34846

PDF 42-11356

Legrandite Image

Images:

Legrandite

Comments: Prismatic crystal of yellow legrandite on a gossanous matrix.
Location: Mina Ojuela, Mapimi, Durango, Mexico. Scale: 2.5 x 1.7 x 1.4 cm.
© Fabre Minerals

Images:

Legrandite

Comments: Yellow crystals of legrandite partially covering an iron-oxide gossan.
Location: Oujela Mine, Mapimi, Durango, Mexico. Scale: Crystal size 6 mm.
© John Veevaert

Legrandite Crystallography

Axial Ratios:

a:b:c =1.612:1:1.2871

Cell Dimensions:

a = 12.8, b = 7.94, c = 10.22, Z = 8; beta = 104.2° V = 1,006.94 Den(Calc)= 4.02

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): 4.08(1), 5.93(0.71), 6.68(0.71),

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] [ 1 0 0] [ 1 1 0] [ 0 0 1]

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

McLean W J , Anthony J W , Finney J J , Laughon R B , American Mineralogist , 56 (1971) p.1147-1154, The crystal structure of legrandite

Physical Properties of Legrandite

Cleavage:

[100] Imperfect

Color:

Yellow, Yellowish orange.

Density:

Diaphaniety:

Translucent

Fracture:

Brittle - Conchoidal - Very brittle fracture producing small, conchoidal fragments.

Habit:

Crystalline - Fine - Occurs as well-formed fine sized crystals.

Habit:

Prismatic - Crystals Shaped like Slender Prisms (e.g. tourmaline).

Hardness:

4-5 - Fluorite-Apatite

Luster:

Vitreous (Glassy)

Streak:

white

Optical Properties of Legrandite

Gladstone-Dale:

CI meas= -0.008 (Superior) - where the CI = (1-KPDmeas/KC)
CI calc= -0.003 (Superior) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1762,KPDmeas= 0.1771,KC= 0.1756

Optical Data:

Biaxial (+), a=1.675-1.702, b=1.69-1.709, g=1.735-1.74, bire=0.0380-0.0600, 2V(Calc)=52-62, 2V(Meas)=50.

Calculated Properties of Legrandite

Electron Density:

r_electron=3.80 gm/cc
note: r_Legrandite=4.02 gm/cc.

Fermion Index

Fermion Index = 0.01774
Boson Index = 0.98226

Photoelectric:

PE_Legrandite= 38.57 barns/electron
U=PE_Legrandite x r_electron= 146.55 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Legrandite is Not Radioactive

Legrandite Classification

Dana Class:

42.6.4.1 (42)Hydrated Phosphates, etc., Containing Hydroxyl or Halogen

(42.6)where (AB)2 (XO4) Zq · x(H2O)

(42.6.4)Dana Group

42.6.4.1 Legrandite Zn2(AsO4)(OH)·(H2O) P 2₁/c 2/m

42.6.4.2 Spencerite Zn4(PO4)2(OH)2·3(H2O) P 2/c 2/m

Strunz Class:

VII/D.07-50 VII - Phosphates, Arsenates and Vanadates

VII/D - Water-bearing phosphates with unfamiliar anions, cations of medium size: Cu, Zn, Mn, Al, Fe

VII/D.07 - Nissonite - Euchroite - Spencerite series

VII/D.07-10 Nissonite Cu2Mg2(PO4)2(OH)2·5(H2O) C 2/c 2/m

VII/D.07-20 Strashimirite Cu8(AsO4)4(OH)4·5(H2O) P 2/m,P 2,Pm Mono

VII/D.07-30 Euchroite Cu2(AsO4)(OH)·3(H2O) P 2₁2₁2₁ 2 2 2

VII/D.07-40 Arhbarite Cu2Mg(AsO4)(OH)3 P1 1

VII/D.07-50 Legrandite Zn2(AsO4)(OH)·(H2O) P 2₁/c 2/m

VII/D.07-60 Spencerite Zn4(PO4)2(OH)2·3(H2O) P 2/c 2/m

VII/D.07-70 Nevadaite! (Cu,[],Al,V)6[Al8(PO4)8F8](H2O)23 P 2₁mn 2 2 2

Other Legrandite Information

References:

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

Search for Legrandite using:

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

Visit our Advertisers for Legrandite :
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 Legrandite Mineral Data :

Ask about Legrandite 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 Legrandite Specimen Label here :

Legrandite

Zn2(AsO4)(OH)·(H2O)
Dana No: 42.6.4.1 Strunz No: VII/D.07-50
Locality:

Notes: