Grechishchevite Mineral Data

General Grechishchevite Information

Chemical Formula:

Hg3S2(Br,Cl,I)2

Composition:

Molecular Weight = 817.84 gm

Mercury 73.58 % Hg 76.51 % Hg₂O

Sulfur 7.84 % S 7.84 % S^2-

- % S -3.91 % -O=S

Iodine 6.21 % I 6.21 % I

- % I -0.39 % -O=I₂

Bromine 9.77 % Br 9.77 % Br

- % Br -0.98 % -O=Br₂

Chlorine 2.60 % Cl 2.60 % Cl

- % Cl -0.59 % -O=Cl₂

______ ______

100.00 % 97.07 % = TOTAL OXIDE

Empirical Formula:

Hg₃S₂BrCl_0.6I_0.4

Environment:

In the oxidation zone in fractures of a mercury deposit.

IMA Status:

Approved IMA 1990

Locality:

Arzak and Kadyrel mercury deposits, Tuva, Siberia, Russia. Link to MinDat.org Location Data.

Name Origin:

Named for Oleg Konstantinovich Grechishchev, Russian engineering geologist, long-time student of mercury ores from Tuva, Siberia.

Name Pronunciation:

Grechishchevite + Pronunciation

Grechishchevite Image

Images:

Grechishchevite

Comments: Red grechishchevite coatings on calcite.
Location: Kadyrel' Hg occurrence, Oorash-Khem River Valley, Uyuk Range, Pii-Khem District, Tuva Republic, Eastern-Siberian Region, Russia. Scale: Picture Size 2 mm.
© Jeff Weissman / Photographic Guide to Mineral Species

Grechishchevite Crystallography

Axial Ratios:

a:c = 1:0.65671

Cell Dimensions:

a = 13.225, c = 8.685, Z = 8; V = 1,519.01 Den(Calc)= 7.15

Crystal System:

Tetragonal Space Group: P 4₂m-,P 4m2,P 4mm,P 4/mmm

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

By Intensity(I/I_o): 2.65(1), 3.02(0.6), 3.95(0.6),

Physical Properties of Grechishchevite

Cleavage:

{???} Good

Color:

Brownish black, Orange, Reddish orange.

Density:

7.16

Diaphaneity:

Transparent

Habit:

Microscopic Crystals - Crystals visible only with microscopes.

Habit:

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

Hardness:

2.5 - Finger Nail

Luster:

Vitreous - Adamantine

Streak:

deep yellow

Optical Properties of Grechishchevite

Dichroism (e):

yellow.

Dichroism (w):

straw yellow.

Gladstone-Dale:

CI meas= 0.091 (Poor) - where the CI = (1-KPDmeas/KC)
CI calc= 0.09 (Poor) - where the CI = (1-KPDcalc/KC)
KPDcalc= 0.1399,KPDmeas= 0.1397,KC= 0.1537
Ncalc = 2.1

Optical Data:

Uniaxial (+), w=2, e=2, bire=0.0000.

RL Color:

Gray wihte with strong internal orange reflections.

Reflectivity

**Standardized Intensity (100%) Reflection Spectra of Grechishchevite in Air**
λ	R₁	R₂	∑ R₁(λ)	∑ R₂(λ)
436 nm	22.80	19.20
460 nm	24.50	22.20
500 nm	21.40	18.90
546 nm	19.80	17.30
590 nm	18.80	16.50
620 nm	18.90	16.70
656 nm	18.10	15.90

**Calculated Relative Intensity Colors of Grechishchevite in Air**
Relative Intensity	0%	60%	100%	120%	180%	240%	300%	360%	420%	480%	530%
R₁
R₂

Calculated Properties of Grechishchevite

Electron Density:

Bulk Density (Electron Density)=5.92 gm/cc
note: Specific Gravity of Grechishchevite =7.15 gm/cc.

Fermion Index:

Fermion Index = 0.22
Boson Index = 0.78

Photoelectric:

PE_{Grechishchevite}=1,293.80 barns/electron
U=PE_{Grechishchevite} x rElectron Density=7,655.34 barns/cc.

Radioactivity:

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

Grechishchevite Classification

Dana Class:

10.03.05.01 (10)Oxyhalides and Hydroxyhalides

(10.03)where (A)3 (O,OH)2 Xq

(10.03.05)Dana Group

10.03.05.01 Grechishchevite Hg3S2(Br,Cl,I)2 P 4₂m-,P 4m2,P 4mm,P 4/mmm Tetra

Strunz Class:

02.FC.15c 02 - SULFIDES and SULFOSALTS (sulfides, selenides, tellurides; arsenides, antimonides, bismuthides; sulfarsenites, sulf

02.F - Sulfides of Arsenic, Alkalies; Sulfides with Halide, Oxide, Hydroxide, H2O

02.FC -With Cl, Br, I (halide-sulfides)

02.FC.15c Grechishchevite Hg3S2(Br,Cl,I)2 P 4₂m-,P 4m2,P 4mm,P 4/mmm Tetra

Other Grechishchevite Information

References:

NAME( Dana8) PHYS. PROP.(Dana8) OPTIC PROP.(AntBidBlaNic3)

See Also:

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

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Grechishchevite

Hg3S2(Br,Cl,I)2
Dana No: 10.03.05.01 Strunz No: 02.FC.15c
Locality:

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