Gratonite Mineral Data

Gratonite Mineral Data +

General Gratonite Information

Chemical Formula:

Pb9As4S15

Composition:

Molecular Weight = 2,645.48 gm

Arsenic 11.33 % As

Lead 70.49 % Pb

Sulfur 18.18 % S

______

100.00 %

Empirical Formula:

Pb₉As₄S₁₅

Environment:

In vugs in hydrothermal copper ores.

IMA Status:

Valid Species (Pre-IMA) 1939

Locality:

In the Excelsior mine, Cerro de Pasco, Peru, in large crystals. Link to MinDat.org Location Data.

Name Origin:

For Louis Carly Graton (1880-1970), Professor of Economic Geology, Harvard University, Cambridge, Massachusetts, USA.

Synonym:

ICSD 18097

PDF 44-1412

Gratonite Image

Images:

Gratonite

Comments: Crystal cluster of gratonite. The largest crystal is 2.5 mm across.
Location: Excelsior mine, Cerro de Pasco, Pasco dept., Peru. Scale: 1.5 x 1 cm.
© John Veevaert

Gratonite Crystallography

Axial Ratios:

a:c = 1:0.4402

Cell Dimensions:

a = 17.701, c = 7.792, Z = 3; V = 2,114.34 Den(Calc)= 6.23

Crystal System:

Trigonal - Ditrigonal PyramidalH-M Symbol (3m) Space Group: R 3m

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

By Intensity(I/I_o): 3.43(1), 3.75(0.6), 2.734(0.5),

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 0 1] [ 4 0 1] [ 0 0 1] [ 1 1 0] [ 1 0 0] [ 0 2 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

Ribar B , Nowacki W , Zeitschrift fur Kristallographie , 128 (1969) p.321-338, Neubestimmung der kristallstruktur von gratonit, Pb9As4S15, Locality: Wiesloch, Germany

Physical Properties of Gratonite

Cleavage:

None

Color:

Lead gray, Dark lead gray.

Density:

6.22

Diaphaniety:

Opaque

Fracture:

Brittle - Generally displayed by glasses and most non-metallic minerals.

Hardness:

2.5 - Finger Nail

Luster:

Metallic

Streak:

black

Optical Properties of Gratonite

RL Color:

White, distinctly yellow against galena.

RL Pleochroism:

Very weak.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Gratonite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	36.90	37.80
420 nm	36.30	37.20
440 nm	35.70	36.60
460 nm	35.30	36.10
480 nm	35.10	35.70
500 nm	34.80	35.40
520 nm	34.50	35.00
540 nm	34.20	34.80
560 nm	34.10	34.60
580 nm	34.00	34.50
600 nm	33.90	34.50
620 nm	33.80	34.40
640 nm	33.70	34.20
660 nm	33.50	33.80
680 nm	33.00	33.40
700 nm	32.40	32.70

**Calculated Relative Intensity Colors of Gratonite in Air**
Relative Intensity	0%	30%	60%	90%	100%	120%	150%	180%	210%	240%	260%
R₁
R₂

Calculated Properties of Gratonite

Electron Density:

r_electron=5.23 gm/cc
note: r_Gratonite=6.23 gm/cc.

Fermion Index

Fermion Index = 0.15714
Boson Index = 0.84286

Photoelectric:

PE_Gratonite=1,299.32 barns/electron
U=PE_Gratonite x r_electron=6,792.88 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Gratonite is Not Radioactive

Gratonite Classification

Dana Class:

3.3.2.1 (3)Sulfides - Sulfosalts

(3.3)where 3 < z/y < 4 - (A+)i (A++)j [By Cz], A=metals, B=semi-metals, C=non-metals

(3.3.2)Dana Group

3.3.2.1 Gratonite Pb9As4S15 R 3m 3m

Strunz Class:

II/E.15-30 II - Sulfides and sulphosalts

II/E - Sulfosalts (S : As,Sb,Bi = x) Lead-Sulfosalts with Arsen and Antimon x = 3.8 - 3.1

II/E.15 - Jordanite - Lengenbachite series

II/E.15-10 Jordanite Pb14(As,Sb)6S23 P 2₁/m 2/m

II/E.15-20 Geocronite Pb14(Sb,As)6S23 P 2₁/m 2/m

II/E.15-30 Gratonite Pb9As4S15 R 3m 3m

II/E.15-40 Meneghinite Pb13CuSb7S24 Pbnm 2/m 2/m 2/m

II/E.15-45 Tsugaruite! Pb4As2S7 Pba2 or Pbam Ortho

II/E.15-50 Lengenbachite Pb6(Ag,Cu)2As4S13 P1 or P1 Tri

Other Gratonite Information

References:

NAME( AntBidBlaNic1) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

Search for Gratonite using:

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

Visit our Advertisers for Gratonite :
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 Gratonite Mineral Data :

Ask about Gratonite 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 Gratonite Specimen Label here :

Gratonite

Pb9As4S15
Dana No: 3.3.2.1 Strunz No: II/E.15-30
Locality:

Notes: