Bournonite
Encyclopedia
Bournonite is a sulfosalt
mineral
species, a sulfantimonite of lead
and copper
with the formula PbCuSbS3.
It was first mentioned by Philip Rashleigh
in 1797 as an ore
of antimony
and was more completely described in 1804 by French crystallographer
and mineralogist Jacques Louis de Bournon (1751–1825), after whom it was named. The name given by Bournon himself (in 1813) was endellione, since used in the form endellionite, after the locality in Cornwall
where the mineral was first found.
The crystals are orthorhombic, and are generally tabular in habit owing to the predominance of the basal pinacoid; numerous smooth bright faces are often developed on the edges and corners of the crystals. Usually, however, the crystals are twinned
, the twin-plane being a face of the prism (m); the angle between the faces of this prism being nearly a right angIe (86 20), the twinning gives rise to cruciform groups and when it is often repeated the group has the appearance of a cog-wheel, hence the name Rdelerz (wheel-ore) of the Kapnik miners. The repeated twinning gives rise to twin-lamellae, which may be detected on the fractured surfaces, even of the massive material.
It is a mineral in medium temperature hydrothermal vein
deposits. It commonly occurs with galena
, tetrahedrite
, sphalerite
, chalcopyrite
, pyrite
, stibnite
, zinkenite
, siderite
, quartz
, rhodochrosite
, dolomite
and barite
.
It was first described for an occurrence in Wheal Boys in the parish of St Endellion
in Cornwall, it was found associated with jamesonite
, sphalerite
and siderite
. Later, still better crystals were found in another Cornish mine, namely, Herodsfoot
mine near Liskeard
, which was worked for argentiferous galena
. Fine crystals of large size have been found with quartz
and siderite in the mines at Neudorf
in the Harz
, and with sphalerite and tetrahedrite
at Cavnic
near Baia Mare
in Romania
. It has been reported from a large number of other localities.
Sulfosalt minerals
Sulfosalt minerals are those complex sulfide minerals with the general formula: AmBnSp; where A represents a metal such as copper, lead, silver, iron and rarely mercury, zinc, vanadium; B usually represents semi-metal such as arsenic, antimony, bismuth and rarely germanium, or metals like tin and...
mineral
Mineral
A mineral is a naturally occurring solid chemical substance formed through biogeochemical processes, having characteristic chemical composition, highly ordered atomic structure, and specific physical properties. By comparison, a rock is an aggregate of minerals and/or mineraloids and does not...
species, a sulfantimonite of lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
and copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
with the formula PbCuSbS3.
It was first mentioned by Philip Rashleigh
Philip Rashleigh
Philip Rashleigh FRS , antiquary and Cornish squire, eldest son of Jonathan Rashleigh, M.P. for Fowey in Cornwall , who married, on 11 June 1728, Mary, daughter of Sir William Clayton of Marden in Surrey, was born at Aldermanbury, London, 28 Dec.1729...
in 1797 as an ore
Ore
An ore is a type of rock that contains minerals with important elements including metals. The ores are extracted through mining; these are then refined to extract the valuable element....
of antimony
Antimony
Antimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
and was more completely described in 1804 by French crystallographer
Crystallography
Crystallography is the experimental science of the arrangement of atoms in solids. The word "crystallography" derives from the Greek words crystallon = cold drop / frozen drop, with its meaning extending to all solids with some degree of transparency, and grapho = write.Before the development of...
and mineralogist Jacques Louis de Bournon (1751–1825), after whom it was named. The name given by Bournon himself (in 1813) was endellione, since used in the form endellionite, after the locality in Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
where the mineral was first found.
The crystals are orthorhombic, and are generally tabular in habit owing to the predominance of the basal pinacoid; numerous smooth bright faces are often developed on the edges and corners of the crystals. Usually, however, the crystals are twinned
Crystal twinning
Crystal twinning occurs when two separate crystals share some of the same crystal lattice points in a symmetrical manner. The result is an intergrowth of two separate crystals in a variety of specific configurations. A twin boundary or composition surface separates the two crystals....
, the twin-plane being a face of the prism (m); the angle between the faces of this prism being nearly a right angIe (86 20), the twinning gives rise to cruciform groups and when it is often repeated the group has the appearance of a cog-wheel, hence the name Rdelerz (wheel-ore) of the Kapnik miners. The repeated twinning gives rise to twin-lamellae, which may be detected on the fractured surfaces, even of the massive material.
It is a mineral in medium temperature hydrothermal vein
Vein (geology)
In geology, a vein is a distinct sheetlike body of crystallized minerals within a rock. Veins form when mineral constituents carried by an aqueous solution within the rock mass are deposited through precipitation...
deposits. It commonly occurs with galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
, tetrahedrite
Tetrahedrite
Tetrahedrite is a copper antimony sulfosalt mineral with formula: 12Sb4S13. It is the antimony endmember of the continuous solid solution series with arsenic bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common...
, sphalerite
Sphalerite
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
, chalcopyrite
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...
, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
, stibnite
Stibnite
Stibnite, sometimes called antimonite, is a sulfide mineral with the formula Sb2S3. This soft grey material crystallizes in an orthorhombic space group. It is the most important source for the metalloid antimony...
, zinkenite
Zinkenite
Zinkenite is a steel-gray metallic sulfosalt mineral composed of lead antimony sulfide Pb9Sb22S42. Zinkenite occurs as acicular needle-like crystals....
, siderite
Siderite
Siderite is a mineral composed of iron carbonate FeCO3. It takes its name from the Greek word σίδηρος sideros, “iron”. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus...
, quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
, rhodochrosite
Rhodochrosite
Rhodochrosite is a manganese carbonate mineral with chemical composition MnCO3. In its pure form, it is typically a rose-red color, but impure specimens can be shades of pink to pale brown. The streak is white. Its Mohs hardness varies between 3.5 and 4. Its specific gravity is 3.5 to 3.7. It...
, dolomite
Dolomite
Dolomite is a carbonate mineral composed of calcium magnesium carbonate CaMg2. The term is also used to describe the sedimentary carbonate rock dolostone....
and barite
Barite
Baryte, or barite, is a mineral consisting of barium sulfate. The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte itself is generally white or colorless, and is the main source of barium...
.
It was first described for an occurrence in Wheal Boys in the parish of St Endellion
St Endellion
St Endellion is a civil parish and village in north Cornwall, England, United Kingdom. The village and parish church are situated four miles north of Wadebridge....
in Cornwall, it was found associated with jamesonite
Jamesonite
Jamesonite is a sulfosalt mineral, a lead, iron, antimony sulfide with formula Pb4FeSb6S14. With the addition of manganese it forms a series with benavidesite. It is a dark grey metallic mineral which forms acicular prismatic monoclinic crystals. It is soft with a Mohs hardness of 2.5 and has a...
, sphalerite
Sphalerite
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
and siderite
Siderite
Siderite is a mineral composed of iron carbonate FeCO3. It takes its name from the Greek word σίδηρος sideros, “iron”. It is a valuable iron mineral, since it is 48% iron and contains no sulfur or phosphorus...
. Later, still better crystals were found in another Cornish mine, namely, Herodsfoot
Herodsfoot
Herodsfoot is a village in southeast Cornwall, United Kingdom. It is situated approximately four miles southwest of Liskeard and five miles north of Looe at a point where two tributaries of the West Looe river join....
mine near Liskeard
Liskeard
Liskeard is an ancient stannary and market town and civil parish in south east Cornwall, England, United Kingdom.Liskeard is situated approximately 20 miles west of Plymouth, west of the River Tamar and the border with Devon, and 12 miles east of Bodmin...
, which was worked for argentiferous galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
. Fine crystals of large size have been found with quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
and siderite in the mines at Neudorf
Neudorf
There are communes and places that have the name Neudorf :-In Austria:*Neudorf bei Staatz, in the district of Mistelbach, Lower Austria*Wiener Neudorf, in the district of Mödling, Lower Austria*Neudorf bei Parndorf, in Burgenland...
in the Harz
Harz
The Harz is the highest mountain range in northern Germany and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart , latinized as Hercynia. The legendary Brocken is the highest summit in the Harz...
, and with sphalerite and tetrahedrite
Tetrahedrite
Tetrahedrite is a copper antimony sulfosalt mineral with formula: 12Sb4S13. It is the antimony endmember of the continuous solid solution series with arsenic bearing tennantite. Pure endmembers of the series are seldom if ever seen in nature. Of the two, the antimony rich phase is more common...
at Cavnic
Cavnic
Cavnic is a former mining town situated in the valley of the same name, east of Baia Mare, in Maramureş County, northern Romania. The town covers , at altitudes ranging from 500 to 1050 meters above sea level.- History :...
near Baia Mare
Baia Mare
Baia Mare is a municipality in northwestern Romania and the capital of Maramureş County. The city is situated about 600 kilometres from Bucharest, the capital of Romania, 70 kilometres from the border with Hungary and 50 kilometres from the border with Ukraine...
in Romania
Romania
Romania is a country located at the crossroads of Central and Southeastern Europe, on the Lower Danube, within and outside the Carpathian arch, bordering on the Black Sea...
. It has been reported from a large number of other localities.