Nagyagite Mineral Data

Nagyagite Mineral Data +

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General Nagyagite Information

Chemical Formula:

AuPb(Sb,Bi)Te2-3S6

Composition:

Molecular Weight = 1,059.12 gm

Bismuth 4.93 % Bi

Antimony 8.62 % Sb

Tellurium 30.12 % Te

Lead 19.56 % Pb

Gold 18.60 % Au

Sulfur 18.17 % S

______

100.00 %

Empirical Formula:

AuPbSb_0.75Bi_0.25Te_2.5S₆

Environment:

Epithermal hydrothermal veins.

IMA Status:

Valid Species (Pre-IMA) 1845

Locality:

Nagyag mine (now Sacaramb), Romania. Link to MinDat.org Location Data.

Name Origin:

Named after the locality.

Synonym:

ICSD 87711

PDF 47-1755

Nagyagite Image

Images:

Nagyagite

Comments: Nagyagite partially covered with calcite.
Location: Sacaramb (Nagyag), Romania. Scale: Crystal size 1 cm.
© John Veevaert

Nagyagite Crystallography

Axial Ratios:

a:c = 1:7.2826

Cell Dimensions:

a = 4.14, c = 30.15, Z = 2; V = 516.76 Den(Calc)= 6.81

Crystal System:

Tetragonal - DisphenoidalH-M Symbol (4) Space Group: P 4

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

By Intensity(I/I_o): 3.02(1), 1.506(0.6), 2.81(0.6),

Crystal Structure:

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Effenberger H , Paar W H , Topa D , Culetto F J , Giester G , American Mineralogist , 84 (1999) p.669-676, Toward the crystal structure of nagyagite, [Pb(Pb,Sb)S2][(Au,Te)]

Physical Properties of Nagyagite

Cleavage:

[010] Perfect

Color:

Lead gray, Black.

Density:

7.5

Diaphaniety:

Opaque

Fracture:

Hackly - Jagged, torn surfaces, (e.g. fractured metals).

Habit:

Granular - Generally occurs as anhedral to subhedral crystals in matrix.

Habit:

Lamellar - Thin laminae producing a lamellar structure.

Habit:

Platy - Sheet forms (e.g. micas).

Hardness:

1.5-2 - Talc-Gypsum

Luminescence:

None.

Luster:

Metallic

Magnetism:

Nonmagnetic

Streak:

gray black

Optical Properties of Nagyagite

RL Anisotrophism:

Weak but distinct.

RL Color:

Gray-white.

RL Pleochroism:

Weak in air and oil.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Nagyagite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
400 nm	43.20	49.00
420 nm	42.80	48.00
440 nm	42.20	47.00
460 nm	41.60	45.90
480 nm	40.90	45.00
500 nm	40.30	44.20
520 nm	39.60	43.50
540 nm	38.80	42.80
560 nm	38.10	42.10
580 nm	37.50	41.50
600 nm	37.00	40.90
620 nm	36.50	40.30
640 nm	36.10	39.80
660 nm	35.50	39.20
680 nm	34.80	38.60
700 nm	34.20	38.00

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

Calculated Properties of Nagyagite

Electron Density:

r_electron=5.74 gm/cc
note: r_Nagyagite=6.81 gm/cc.

Fermion Index

Fermion Index = 0.06866
Boson Index = 0.93134

Photoelectric:

PE_Nagyagite= 892.17 barns/electron
U=PE_Nagyagite x r_electron=5,116.97 barns/cc.

Radioactivity:

GRapi = 0 (Gamma Ray American Petroleum Institute Units)

Nagyagite is Not Radioactive

Nagyagite Classification

Dana Class:

2.11.10.1 (2)Sulfides - Including Selenides and Tellurides

(2.11)where Am Bn Xp, with (m+n):p=2:3

(2.11.10)Dana Group

2.11.10.1 Nagyagite AuPb(Sb,Bi)Te2-3S6 P 4 4

Strunz Class:

II/D.15-20 II - Sulfides and sulphosalts

II/D - Sulfides with metal: sulfur, selenium and tellurium < 1:1, Tellurides with Copper, Silver, Gold

II/D.15 - Montbrayite - Buckhornite series

II/D.15-10 Montbrayite (Au,Sb)2Te3 P1 1

II/D.15-20 Nagyagite AuPb(Sb,Bi)Te2-3S6 P 4 4

II/D.15-30 Buckhornite AuPb2BiTe2S3 P mmm 2/m 2/m 2/m

Other Nagyagite Information

References:

NAME( Duda&Rejl90) PHYS. PROP.(Enc. of Minerals,2nd ed.,1990) OPTIC PROP.(AntBidBlaNic1)

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Print or Cut-and-Paste your Nagyagite Specimen Label here :

Nagyagite

AuPb(Sb,Bi)Te2-3S6
Dana No: 2.11.10.1 Strunz No: II/D.15-20
Locality:

Notes: