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A paper about pyrite mineral and it's physical and chemical properties and it's formation and genesis and the minerals associated with each and economic uses of it
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Introduction to pyrite
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Introduction to pyrite
Aknowledgement ..………………………………………………………………………….(2)
Introduction …………………………………………………………………………………….(3)
General Characteristics ……………………………………………………………..…..(4)
Structure and crystal Habit ………………………………………………………..…(6)
Pyrite Formation ………………………………………………………………………….…..(7)
Occurrence of Pyrite in Recent Sediments ………………………………..…….(9)
Concentration of Pyrite in Sedimentary Rocks ………………………………(11)
Mechanism of Pyrite Formation in Recent Sediments ………………..…..(12)
pyrite destribution in Egypt …………………………………………………………..(14)
pyrite in Dabbabiya GSSP ……………………………………………………………..(16)
Uses ……………………………………………………………………………………………(17)
Marcasite pyrite (Gemstone) ………………………………………………………..(19)
Distinguishing similar minerals ………………………………………………………(19)
Hazards …………………………………………………………………………………………(20)
References ………………………………………………………………………………….(22)
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Introduction to pyrite
First and above all Thanks to Allah
And my family for their great effort and encouragement
And I want to express my great thanks to:
Prof. Dr. Mohamed Abdallah Gad
Head of geology department and the supervisor of the research
For his continuous support from the start to the end of my way and for
providing me with the sources and the data used in this paper
And thanks to all geology staff member and my friends
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Introduction to pyrite
Iron Sulphides are widespread throughout the geological record. Pyrite,
the most common, occurs in a variety of rock types and environments;
its presence as a major mineral in stratiform ore bodies makes it
extremely important as an indicator of the depositional conditions
under which such bodies are formed.
and it’s an important indicator for many economic minerals and ores as
Gold and silver and many other minerals that is found associated with.
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Introduction to pyrite
General Characteristics
The mineral pyrite, or iron pyrite, also known as fool's gold, is an iron
sulfide with the chemical formula FeS2 (iron (II) disulfide). Pyrite is
considered the most common of the sulfide minerals.
Pyrite's metallic luster and pale brass-yellow hue give it a superficial
resemblance to gold, hence the well-known nickname of fool's gold.
The color has also led to the nicknames brass, brazzle, and Brazil,
primarily used to refer to pyrite found in coal.
The name pyrite is derived from the Greek πυρίτης (pyritēs)
- AKA pyrite lithos - "of fire" or "in fire", in turn from πύρ (pyr), "fire".
In ancient Roman times, this name was applied to several types of
stone that would create sparks when struck against steel; Pliny the
Elder described one of them as being brassy, almost certainly a
reference to what we now call pyrite.
Pyrite is usually found associated with other sulfides or oxides in quartz
veins, sedimentary rock as Limestone, shale, and metamorphic rock like
schist, as well as in coal beds and as a replacement mineral in fossils,
but has also been identified in the sclerites of scaly-foot gastropods.
Despite being nicknamed fool's gold, pyrite is sometimes found in
association with small quantities of gold. Gold and arsenic occur as a
coupled substitution in the pyrite structure. In the Carlintype gold
deposits, arsenian pyrite contains up to 0.37% gold by weight.
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Introduction to pyrite
Category Sulfide mineral
Formula FeS2
Color Pale brass-yellow
Crystal system Isometric
Space group Pa3
Formula mass 119.98 g/mol
Crystal habit Cubic, octahedral and
pyritohedron. Often inter-grown, massive,
radiated, granular, globular, and
Twinning Penetration and contact
Cleavage Indistinct on {001}; partings on
{011} and {111}
Tenacity Brittle
Mohs scale hardness 6 6.5
Luster Metallic
Streak Greenish-black
to brownish-black
Diaphaneity Opaque
Specific gravity 4.955.10
Density 4.85 g/cm3
Fusibility 2.53
Solubility Insoluble in
Other characteristics Paramagnetic
Table 1 showing the general characteristics of pyrite minerals
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Introduction to pyrite
Structure and crystal Habit
Pyrite is an iron (II) disulfide with a
NaCl-type structure.
The S22- groups are situated at the
cube center and the midpoints of
cube edges, and the low-spin FeII
atoms are located at the corners
and face centers.
The arrangement of the disulfide
dumbbells is such that the
structure, although cubic, has a
relatively low symmetry, space
group Pa3. The structure has 3-fold
axes along the [111] directions and 2-fold axes along the [100]
directions. The 2-fold symmetry means that the [100], [010], and
[001] zone axes (equivalent to the a, b, and c crystallographic
axes) are crystallographically not interchangeable with each other
by a simple 90° rotation as in simple cubes. One result of this
structure is that pyrite, along with several other minerals, exhibits
chirality. Thus Guevrement et al. demonstrated that there are
significant differences in the sensitivity of pyrite to oxidation of
the (100) and (111) planes. This chirality of pyrite has been
theoretically exploited in the involvement of pyrite in the
adsorption of organic molecules and, consequently, in prebiotic
syntheses implicated in the origins of life.
(Figure II - Structural Elements of Pyrite.)
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Introduction to pyrite
Pyrite Formation
1. by Hydrothermal Replacement
Magnetite replacement by Pyrite and hydrothermal mineral replacement reactions
Many sulfide minerals form either from reactions involving
hydrothermal fluids or recrystallize under the influence of
hydrothermal fluids. Among them, pyrite (cubic FeS2) is probably
the most widespread sulfide mineral in the Earth’s crust
(Craig and Vokes, 1993). Gold mineralization is often closely
associated with pyrite (Cook and Chryssoulis, 1990; Fleet and
Mumin, 1997; Newton et al., 1998; Sung et al., 2009).
And in numerous gold deposits, magnetite (Fe3O4) is closely
associated with the formation of pyrite. For example, the
magnetite-rich bands and disseminated magnetites in the Paringa
Basalt (1) have been replaced by pyrite during Au-related
hydrothermal activity (Palin and Xu, 2000). Another class of Au
deposits is associated with the replacement of magnetite- rich
Banded Iron Formations (BIFs) by pyrite under hydrothermal
conditions (see e.g., Brown et al., 2003; Pal and Mishra, 2003;
Hammond and Moore, 2006; Andrianjakavah et al., 2007). In all
the above cases, there is consensus that pyrite forms via
sulfidation of magnetite in the presence of sulfur-bearing fluids.
2. Pyrite formation from aqueous solutions
Much work has been devoted to understand the formation of
pyrite and marcasite (orthorhombic FeS2) in aqueous solutions
under diagenetic and hydrothermal conditions.
Most studies emphasized the role of a fine-grained precursor
phase, most commonly a 'FeS' phase and sometimes a Fe-oxy-
In contrast, only a few studies demonstrate pyrite nucleation
directly from a hydrothermal fluid.
(1) (Eastern Goldfields of the Archaean Yilgarn, Western Australia)
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Introduction to pyrite
Pyrite and marcasite formations have been extensively studied
using a FeS precursor at temperatures up to 300 C. For example,
pyrite and marcasite can be produced simply by heating
amorphous FeS and/or pyrrhotite in the presence of H2S (aq)
(Korolev and Kozerenko, 1965; Drobner et al., 1990).
Sulfidation of troilite and mackinawite with H2S (aq) at
temperatures between 100 and 160 C also produced pyrite within
a few days (Taylor et al., 1979a, b). Rickard (1975) synthesized
pyrite from FeS between 20 and 50 C in the presence of elemental
sulfur and H2S (aq), and emphasized the role of polysulfides (S2n)
in pyrite formation in these low temperature environments.
Schoonen and Barnes (1991a, b, c) investigated the formation of
Fe disulfide from an Fe monosulfide precursor by studying the
aging of the precipitates formed upon mixing of a ferrous solution
and hydrogen sulfide, as a function of time, sulfur source, acidity,
and temperature (up to 300 C). In addition, Benning et al. (2000)
studied pyrite formation from mackinawite (nominally written as
FeS) below 100 C and over a wide pH range of 3.3 12.5.
Diagrammatic representation of the overall process of sedimentary pyrite formation. (After BERNER, 1972).
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Introduction to pyrite
Occurrence of Pyrite in Recent Sediments
DUNHAM (1961) has summarised a number of sedimentary
environments where black muds contain pyrite. He lists the following
1. Ill-drained terrestrial swamps,
2. Eutrophic (highly nutrient) lakes,
3. River estuaries, tidal lagoons, and tops of deltas,
4. Deep, land locked sea basins separated by sills from the open ocean,
5. Basins in the sea bottom.
In all these environments (apart from illdrained terrestrial swamps),
under which pyrite forms there appears to be a narrow range of Eh and
The maximum concentration of pyrite which is attained appears to be
between 1-5%. Most measurements indicate that the pH of the
sediment is between 7-8, and Eh measurements show that anaerobic
conditions are present (see Table 2).
Sediment Locality
Pyrite content
Dead Sea
(NEEV and EMERY 1967)
Some pyrite
- 300 m.v.
Wadden Sea
Pyrite present
W. Coast of N. Africa
(REGNELI. 1961)
0.26 - 1.8%
Santa Barbara Basin, California
- 150 bis - 250 m.v.
Central Gulf of California
(BERNER 1964)
0.6 - 1.5%
Table 1. Features of recent sediments.
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Introduction to pyrite
Some workers have noted exceptions to these conclusions. REGNELL
(1961) observed a close correlation between the dissolution of
carbonate and the formation of pyrite, and showed that there is a clear
tendency towards lower pH values in beds rich in pyrite. He suggested
that this decrease in pH accompanies the formation of H2S and CO2 by
the decomposition of organic matter, which he thought plays a decisive
role in FeS2 formation. A similar effect has been noted in the Old Sea
clays of the Wadden Sea area, where pyrite is concentrated around
organic material such as peat detritus and remains of roots of reed
OPPENHEIMER(1960) points out that many chemical changes take
place in a localised area of sediment during decomposition of a large
piece of organic matter. Oxygen is consumed first, then sulphide is
produced by anaerobic bacteria and the pH may decrease. As
decomposition proceeds the organic material is used up and the
bacterial activities begin to decline. When the oxygen demand is less
than the rate of diffusion into the area, aerobic conditions will return
and pH will rise.
KAPLAN, EMERY and RITTENBERG (1963), in their study of basin
sediments of the coast of Southern California, how that pyrite is the
dominant form of sulphur, and that it occurs in an oxidising as well as a
reducing environment.They postulate that the bundant pyrite which is
found in the oxidised layers of the Santa Catalina basin was formed in
micro-environments of reduced nature within the oxidised zone.
However, they come to the conclusion that this does not explain the
relative abundance of pyrite in different environments, and they
suggest that no clue exists to explain what determines the amount
found in a particular sediment.
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Introduction to pyrite
Concentration of Pyrite in Sedimentary Rocks
Black shales are unique amongst sedimentary rocks because of the
concentrations of sulphides found in them, and as a result have
received considerable attention by workers in the field of sulphide
The Chattanooga Shale of Tennessee is typical of this type of sediment,
and investigations by Bares and STRAHL (1957), CONANT and
SWANSON (1961), and STRAHL (1958), show that they contain as much
as 15% pyrite and marcasite and 15 20 % organic matter, although
concentrations are usually less than this amount.
CONANT and SWANSON state that the minute spherules of pyrite in
these shales probably formed during or shortly after black mud
deposition, but larger masses may have resulted from short-distance
migration of the sulphurous compounds while the muds were still
unconsolidated. A bed of pyrite-rich siltstone on the northern edge of
the Nashville Basin, 2" to 3" thick, contains roughly 50 % FeS2.
STRAHL examined shales from Chattanooga, the Permian from Ohio,
the Alum Shales of Sweden, and the Upper Carboniferous shale of St.
Hippolyte, France, and showed that pyrite varies sympathetically with
carbon and antipathetically with ferric iron.
DEANS (1950) and hIRST and DUNHAM (1963) have investigated the
chemistry and petrography of the marl slate, Durham, S. E. England,
and their results show that it contains 0.5% to 6.45% FeS2. These slates
are black and dark grey, and the sulphides are interpreted as being
diagenetic, having precipitated within a foul mud and crystallised as
sulphides in the coarser clean or sandy carbonate layers in which there
was freer permeation as water was expelled from the mud prior to
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Introduction to pyrite
Mechanism of Pyrite Formation in Recent Sediments
A number of mechanisms have been postulated for the formation of
pyrite in recent sediments. In all cases it is suggested that the sulphide
is derived by the reduction of sulphate present in sea water, although
in some cases a small quantity of sulphur is thought to be obtained
from organic material. Pyrite is thought to be formed through an
intermediate iron suliphde, FeS.
BERNER (1967) explains the absence of black FeS in the sediments from
the central gulf of California by assuming that there has been a
relatively rapid transformation of FeS to FeS2 at the sediment water
interface where an abundant supply of both oxidising agent and
reactive sulphur is available.
EMERY and RITTENBERG (1952) also remarked on the absence of black
FeS in the sediments which they examined, and suggested that the
reasons for this absence were:
A slow rate of deposition which enabled the transformation of
FeS + FeS2 to go to completion.
Extremely slow reaction between resistant iron compounds and
H2S would enable direct formation of pyrite.
Evidence produced by KAPLAN et al. (1963) supports the suggestion
that pyrite forms by the direct reaction of the iron sulphide
hydrotroilite and elemental sulphur
FeS + S FeS2
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Introduction to pyrite
KAPLAN et al. present evidence based on the isotopic composition of
pyrite in this
locality which suggests that the mineral formed at different rates in
adiacent micro-environments; VOLKOV (1961) ascribes the presence of
black FeS at depth in the Black Sea to the insufficient concentration of
elemental sulphur for the complete transformation
Many of the conclusions outlined above agree with experimental work
which has been carried out, particularly by BERNER (1964), but the
actual mechanisms of pyrite formation have not been investigated in
any great detail.
FeS + S FeS2
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Introduction to pyrite
pyrite destribution in Egypt mines
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Introduction to pyrite
22.0km (13.7 miles)
274.9° (W)
A Samut Mine, Eastern Desert, Red Sea
29.3km (18.2 miles)
336.4° (NNW)
B Mueilha mine, Eastern Desert, Red Sea
37.8km (23.5 miles)
323.2° (NW)
C Dungash Mine, Eastern Desert, Red Sea
53.8km (33.4 miles)
68.9° (ENE)
D Hanglaliya, Eastern Desert, Red Sea
54.3km (33.7 miles)
326.5° (NNW)
E Barramiya Mine, Barramiya, Eastern Desert, Red Sea
67.6km (42.0 miles)
94.6° (E)
F Abu Rusheid, Sikait-Zabara region, Eastern Desert,
Red Sea
69.3km (43.1 miles)
94.5° (E)
G Wadi Nuqrus (Wadi Nugrus), Emerald mines (incl.
Gebel Zabara; Wadi Abu Rusheid; Wadi Gimal; Wadi
Sikait; Wadi Umm Debaa; Wadi Umm Kabu), Sikait-
Zabara region, Eastern Desert, Red Sea
69.6km (43.3 miles)
64.7° (ENE)
H Sukari gold mine, Marsa Alam, Eastern Desert, Red
74.6km (46.4 miles)
186.5° (S)
I Gabbro Akarem Cu-Ni deposit, Eastern Desert, Red
80.6km (50.1 miles)
69.7° (ENE)
J Atud mine, Marsa Alam, Eastern Desert, Red Sea
90.0km (55.9 miles)
122.2° (ESE)
K Samiuki Mine, Um Samiuki, Eastern Desert, Red Sea
99.4km (61.8 miles)
29.2° (NNE)
L Um Rus Mine, Eastern Desert, Red Sea
124.6km (77.4 miles)
4.6° (N)
M El-Sibai shear zone, Eastern Desert, Red Sea
130.1km (80.8 miles)
1.1° (N)
N El Atshan mine, Central Eastern Desert, Eastern
Desert, Red Sea
144.6km (89.9 miles)
358.0° (N)
O Wadi Kariem, Central Eastern Desert, Eastern
Desert, Red Sea
156.7km (97.3 miles)
341.8° (NNW)
P El Sid Mine, Qift area (Kift area; Coptos area),
Eastern Desert, Red Sea
175.0km (108.7 miles)
341.1° (NNW)
Q Atalla mine, Eastern Desert, Red Sea
183.5km (114.1 miles)
345.8° (NNW)
R Fawakhir Mine, Qift area (Kift area; Coptos area),
Eastern Desert, Red Sea
190.8km (118.5 miles)
349.0° (N)
S Gabal Um Halham, Eastern Desert, Red Sea
201.6km (125.2 miles)
341.8° (NNW)
T Gidami (Aradiya; Eradiya; Sirbakis), Eastern Desert,
Red Sea
203.8km (126.6 miles)
346.1° (NNW)
U Semna mine, Bir Semna, Eastern Desert, Red Sea
216.5km (134.5 miles)
143.9° (SE)
V El-Anbat, Wadi Hodein, Eastern Desert, Red Sea
218.7km (135.9 miles)
193.1° (SSW)
W Abu Swayel Cu-Ni deposit, Wadi Haimur, Wadi
Allaqi District, Eastern Desert, Red Sea
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Introduction to pyrite
pyrite in Dabbabiya GSSP
the topmost part of Esna-1 member (paleocene) in Dabbabiya GSSP is
enriched in pyrite mineral (khozayem 2015).
Lithology and description of the NW and E sections correlated with the GSSP; field
photograph focuses on the P/E boundary and the contact between Esna-1 and Esna-2.
Note the presence of a continuous layer of anhydrite is located 2 cm above the PEB.
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Introduction to pyrite
Pyrite enjoyed brief popularity in the 16th and 17th centuries as a
source of ignition in early firearms, most notably the wheellock,
where the cock held a lump of pyrite against a circular file to strike
the sparks needed to fire the gun.
Pyrite has been used since classical times to manufacture
copperas (iron (II) sulfate). Iron pyrite was heaped up and allowed
to weather (an example of an early form of heap leaching). The
acidic runoff from the heap was then boiled with iron to produce
iron sulfate. In the 15th century, new methods of such leaching
began to replace the burning of sulfur as a source of sulfuric acid.
By the 19th century, it had become the dominant method
Pyrite remains in commercial use for the production of sulfur
dioxide, for use in such applications as the paper industry, and in
the manufacture of sulfuric acid. Thermal decomposition of pyrite
into FeS (iron (II) sulfide) and elemental sulfur starts at 540 °C; at
around 700 °C pS2 is about 1 atm.
A newer commercial use for pyrite is as the cathode material in
Energizer brand non-rechargeable lithium batteries.
Pyrite is a semiconductor material with a band gap of 0.95 eV.
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Introduction to pyrite
During the early years of the 20th century, pyrite was used as a
mineral detector in radio receivers, and is still used by crystal
radio hobbyists. Until the vacuum tube matured, the crystal
detector was the most sensitive and dependable detector
available with considerable variation between mineral types and
even individual samples within a particular type of mineral. Pyrite
detectors occupied a midway point between galena detectors and
the more mechanically complicated perikon mineral pairs. Pyrite
detectors can be as sensitive as a modern 1N34A germanium
diode detector.
Pyrite has been proposed as an abundant, inexpensive material in
low-cost photovoltaic solar panels, Synthetic iron sulfide was used
with copper sulfide to create the photovoltaic material.
Pyrite is used to make marcasite jewelry. Marcasite jewelry, made
from small faceted pieces of pyrite, often set in silver, was known
since ancient times and was popular in the Victorian era.
At the time when the term became common in jewelry making,
"marcasite" referred to all iron sulfides including pyrite, and not to
the orthorhombic FeS2 mineral marcasite which is lighter in color,
brittle and chemically unstable, and thus not suitable for jewelry
making. Marcasite jewelry does not actually contain the mineral
China represents the main importing country with an import of
around 376,000 tones, which resulted at 45% of total global
imports. China is also the fastest growing in terms of the
unroasted iron pyrites imports, with a CAGR of +27.8% from 2007
to 2016. In value terms, China ($47M) constitutes the largest
market for imported unroasted iron pyrites worldwide, making up
65% of global imports.
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Introduction to pyrite
Distinguishing similar minerals
It is distinguishable from native gold by its hardness, brittleness and
crystal form. Natural gold tends to be anhedral (irregularly shaped),
whereas pyrite comes as either cubes or multifaceted crystals. Pyrite
can often be distinguished by the striations which, in many cases, can
be seen on its surface. Chalcopyrite is brighter yellow with a greenish
hue when wet and is softer (3.5 4 on Mohs' scale). Arsenopyrite is
silver white and does not become more yellow when wet.
Iron pyrite is unstable at Earth's surface: iron pyrite exposed to air and
water decomposes into iron oxides and sulfate. This process is
hastened by the action of Acidithiobacillus bacteria which oxidize the
pyrite to produce ferrous iron and sulfate. These reactions occur more
rapidly when the pyrite is in fine crystals and dust, which is the form it
takes in most mining operations
- Acid drainage
Sulfate released from decomposing pyrite
combines with water, producing sulfuric
acid, leading to acid rock drainage. An
example of acid rock drainage caused by
pyrite is the 2015 Gold King Mine waste
water spill.
A pyrite cube
(center) has
dissolved away
from a host rock,
leaving behind
trace gold.
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Introduction to pyrite
- Dust explosions
Pyrite oxidation is sufficiently exothermic that underground coal mines
in high-sulfur coal seams have occasionally had serious problems with
spontaneous combustion in the mined-out areas of the mine.
The solution is to hermetically seal the mined-out areas to exclude
In modern coal mines, limestone dust is sprayed onto the exposed coal
surfaces to reduce the hazard of dust explosions. This has the
secondary benefit of neutralizing the acid released by pyrite oxidation
and therefore slowing the oxidation cycle, thus reducing the likelihood
of spontaneous combustion. In the long term, however, oxidation
continues, and the hydrated sulfates formed may exert crystallization
pressure that can expand cracks in the rock and lead eventually to roof
- Weakened building materials
Building stone containing pyrite tends to stain brown as the pyrite
oxidizes. This problem appears to be significantly worse if any
marcasite is present. The presence of pyrite in the aggregate used to
make concrete can lead to severe deterioration as the pyrite oxidizes.
In early 2009, problems with Chinese drywall imported into the United
States after Hurricane Katrina were attributed to oxidation of pyrite,
which releases hydrogen sulfide gas. These problems included a foul
odor and corrosion of copper wiring. In the United States, in Canada,
and more recently in Ireland, where it was used as under floor infill,
pyrite contamination has caused major structural damage. Modern
tests for aggregate materials certify such materials as free of pyrite.
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Introduction to pyrite
1- (The Chemistry of Pyrite Formation in Aqueous Solution and its Relation to the
Depositional Environment)
Baas-Becldng Geobiological Research Laboratory, Canberra, Australia
C.S.I.R.0., Division of Mineral Chemistry, Port Melbourne, Australia
Dept. of Chemistry, University of Melbourne, Melbourne, Australia
2- pyrite destribution in Egypt
Helmy, H. M., & Kaindl, R. (1999). Mineralogy and fluid inclusion studies of the Au-Cu quartz veins in
the Hamash area, South-Eastern Desert, Egypt. Mineralogy and Petrology, 65(1-2), 69-86.; Hilmy, M.
E., & Osman, A. (1989). Remobilization of gold from a chalcopyrite-pyrite mineralization Hamash gold
mine, Southeastern Desert, Egypt. Mineralium Deposita, 24(4), 244-249.; Zoheir, B., Deshesh, F.,
Broman, C., Pitcairn, I., El-Metwally, A., & Mashaal, S. (2018). Granitoid-associated gold
mineralization in Egypt: a case study from the Atalla mine. Mineralium Deposita, 53(5), 701-720.
3- New geochemical constraints on the PaleoceneEocene thermal maximum:
Dababiya GSSP, Egypt
Hassan Khozyema,b,, Thierry Adatte b, Jorge E. Spangenberg c, Gerta Keller d, Abdel Aziz Tantawy a,
Alexey Ulianov b
a Department of Geology, Faculty of Sciences, Aswan University, Aswan, Egypt
b Institute of Earth Sciences (ISTE), University of Lausanne, 1015 Lausanne, Switzerland
c Institute of Earth Surface Dynamics (IDYST), University of Lausanne, Switzerland, 1015 Lausanne, Switzerland
d Department of Geosciences, Princeton University, Guyot Hall, Princeton, NJ 08544, USA
4- Sedimentary pyrite formation: An update
Department of Geology and Geophysics, Yale University, New Haven.
(Received November 7, 1983; accepted December 5, 1983)
5- Distribution of pyrite mineral in Egypt mines map
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Introduction to pyrite
for questions and more information contact me at:
Tel: +2 01154411722
... Weathering of land and rocks including open-pit mining for metals, sulphides and lignite and the smelting of ores are the main sources for sulphate from mine water bearing sulphate such as gypsum sulphate mineral (calcium sulphate dihydrate) [15] and the oxidized form of sulphate minerals as pyrite (FeS 2 ) [16,17] is a natural source of high sulphate concentration. When metal sulphide (FeS 2 ) is exposed to atmosphere, it produces sulphate rich and acidic effluents (Eq. ...
Sulphate (SO4²⁻) is a common anion nutrient naturally occurs in water bodies, and considered not toxic when presented in low concentration. However, the presence of large amounts of SO4²⁻ induces sour taste in household water and scaling in pipe lines. A concentration of 500 to 750 mg(SO4²⁻)/L causes laxative effect, dehydration, and gastrointestinal irritation in human bodies. Hence, strict limitation was imposed on SO4²⁻ discharge, to conform with regulatory bodies standards. Several techniques were developed to eliminate or minimize the SO4²⁻ content in wastewater discharges. Generally, chemical precipitation method widely utilized for SO4²⁻ mitigation from high SO4²⁻ concentration sources particularly mine wastewater. However, the drawback of this process is that the theoretically obtainable minimum sulphate concentration with lime precipitation is 1500 mg/L SO4²⁻ at ambient temperature due to high solubility of gypsum. In the present review, the traditional and recently developed sulphate removal techniques are discussed by addressing their merits/drawbacks and potential further improvements. Moreover, novel integrated system which combines one or more advanced techniques in parallel with the established methods are reviewed that could pave the way towards the development of suitable technology. Finally, the life cycle assessment and techno-economic analysis are discussed for the various technologies.
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Gold-bearing sulfide-quartz veins cutting mainly through the Atalla monzogranite intrusion in the Eastern Desert of Egypt are controlled by subparallel NE-trending brittle shear zones. These veins are associated with pervasive sericite-altered, silicified, and ferruginated rocks. The hosting shear zones are presumed as high-order structures of the Najd-style faults in the Central Eastern Desert (~ 615–585 Ma). Ore minerals include an early pyrite-arsenopyrite (±pyrrhotite) mineralization, partly replaced by a late pyrite-galena-sphalerite-chalcopyrite (±gold/electrum ± tetrahedrite ± hessite) assemblage. Gold occurs as small inclusions in pyrite and arsenopyrite, or more commonly as intergrowths with galena and sphalerite/tetrahedrite in microfractures. Arsenopyrite geothermometry suggests formation of the early Fe-As-sulfide mineralization at 380–340 °C, while conditions of deposition of the late base metal-gold assemblage are assumed to be below 300 °C. Rare hessite, electrum, and Bi-galena are associated with sphalerite and gold in the late assemblage. The early and late sulfide minerals show consistently a narrow range of δ³⁴S ‰ (3.4–6.5) that overlaps with sulfur isotopic values in ophiolitic rocks. The Au-quartz veins are characterized by abundant CO2 and H2O ± CO2 ± NaCl inclusions, where three-dimensional clusters of inclusions show variable aqueous/carbonic proportions and broad range of total (bimodal) homogenization temperatures. Heterogeneous entrapment of immiscible fluids is interpreted to be caused by unmixing of an originally homogenous, low salinity (~ 2 eq. mass % NaCl) aqueous-carbonic fluid, during transition from lithostatic to hydrostatic conditions. Gold deposition occurred generally under mesothermal conditions, i.e., 1.3 kbar and ~ 280 °C, and continued during system cooling to < 200 °C and pressure decrease to ~ 0.1 kbar. Based on the vein textures, sulfur isotope values, composition of ore fluids, and conditions of ore formation, we suggest that the Atalla monzogranite intrusion acted only as a competent structural host for ore deposition from shear-related, metal-rich fluids migrated up from depth. This model is also presumed for most granitoid-associated Au deposits in the region, considering the similarity in their structural control, alteration pattern and mineralogy, and chemistry of the ore fluids.
Remobilization of gold from a chalcopyrite-pyrite mineralization Hamash gold mine, Southeastern Desert
  • H M Helmy
  • R Kaindl
  • M E Hilmy
  • A Osman
  • B Zoheir
  • F Deshesh
  • C Broman
  • I Pitcairn
  • A El-Metwally
  • S Mashaal
Helmy, H. M., & Kaindl, R. (1999). Mineralogy and fluid inclusion studies of the Au-Cu quartz veins in the Hamash area, South-Eastern Desert, Egypt. Mineralogy and Petrology, 65(1-2), 69-86.; Hilmy, M. E., & Osman, A. (1989). Remobilization of gold from a chalcopyrite-pyrite mineralization Hamash gold mine, Southeastern Desert, Egypt. Mineralium Deposita, 24(4), 244-249.; Zoheir, B., Deshesh, F., Broman, C., Pitcairn, I., El-Metwally, A., & Mashaal, S. (2018). Granitoid-associated gold mineralization in Egypt: a case study from the Atalla mine. Mineralium Deposita, 53(5), 701-720.