Guettardite is a rare arsenic

Arsenic

Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...

-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...

 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...

 sulfosalt mineral with formula Pb(Sb,As)₂S₄. It forms gray black metallic prismatic to acicular crystals with monoclinic symmetry. It is a dimorph

Polymorphism (materials science)

Polymorphism in materials science is the ability of a solid material to exist in more than one form or crystal structure. Polymorphism can potentially be found in any crystalline material including polymers, minerals, and metals, and is related to allotropy, which refers to chemical elements...

 of the triclinic twinnite.

Discovery and occurrence

It was first described in 1967 for an occurrence in the Taylor Pit, Madoc

Madoc

Madoc or Madog ab Owain Gwynedd was, according to folklore, a Welsh prince who sailed to America in 1170, over three hundred years before Christopher Columbus's voyage in 1492. According to the story, he was a son of Owain Gwynedd who took to the sea to flee internecine violence at home...

, Hastings County, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

, Canada. It was named for French naturalist Jean-Étienne Guettard

Jean-Étienne Guettard

Jean-Étienne Guettard , French naturalist and mineralogist, was born at Étampes, near Paris.In boyhood, he gained a knowledge of plants from his grandfather, who was an apothecary, and later he qualified as a doctor in medicine...

 (1715-1786).

It occurs in hydrothermal veins

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...

 within marble

Marble

Marble is a metamorphic rock composed of recrystallized carbonate minerals, most commonly calcite or dolomite.Geologists use the term "marble" to refer to metamorphosed limestone; however stonemasons use the term more broadly to encompass unmetamorphosed limestone.Marble is commonly used for...

 at the type locality

Type locality (geology)

Type locality , also called type area or type locale, is the where a particular rock type, stratigraphic unit, fossil or mineral species is first identified....

 in Modoc. It occurs associated with 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...

, 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...

, wurtzite

Wurtzite

Wurtzite is a zinc iron sulfide mineral a less frequently encountered mineral form of sphalerite. The iron content is variable up to eight percent. It is trimorphous with matraite and sphalerite....

, 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...

, 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...

, orpiment

Orpiment

Orpiment, As2S3, is a common monoclinic arsenic sulfide mineral. It has a Mohs hardness of 1.5 to 2 and a specific gravity of 3.46. It melts at 300 °C to 325 °C...

, realgar

Realgar

Realgar, α-As4S4, is an arsenic sulfide mineral, also known as "ruby sulphur" or "ruby of arsenic". It is a soft, sectile mineral occurring in monoclinic crystals, or in granular, compact, or powdery form, often in association with the related mineral, orpiment . It is orange-red in colour, melts...

, enargite

Enargite

Enargite is a copper arsenic sulfosalt mineral with formula: Cu3AsS4. It takes its name from the Greek word enarge, "distinct." Enargite is a steel gray, blackish gray, to violet black mineral with metallic luster. It forms slender orthorhombic prisms as well as massive aggregates...

, 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...

, zinkenite

Zinkenite

Zinkenite is a steel-gray metallic sulfosalt mineral composed of lead antimony sulfide Pb9Sb22S42. Zinkenite occurs as acicular needle-like crystals....

, jordanite

Jordanite

Jordanite is a sulfosalt mineral with chemical formula Pb146S23 in the monoclinic crystal system, named after the German scientist Dr H. Jordan who discovered it in 1864....

, bournonite

Bournonite

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 , after...

, sterryite, boulangerite

Boulangerite

Boulangerite is a sulfosalt mineral, lead antimony sulfide, formula Pb5Sb4S11. It was named in 1837 in honor of French mining engineer Charles Boulanger. It forms metallic grey monoclinic crystals. Sometimes the crystals form a fine feathery mass which has been called plumosite....

, 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...

 and sartorite at Madoc.

In addition to the type locality, it has been reported from the Brobdingnag mine, near Silverton

Silverton

Silverton has many uses:*Places:** United States*** Silverton, Colorado*** Silverton, New Jersey*** Silverton, Oregon*** Silverton, Ohio*** Silverton, Texas*** Silverton, Washington*** Silverton, Wyoming*** Silverton Township, Minnesota** Elsewhere...

, Colorado

Colorado

Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

; the Jas Roux deposit in
Hautes-Alpes

Hautes-Alpes

Hautes-Alpes is a department in southeastern France named after the Alps mountain range.- History :Hautes-Alpes is one of the original 83 departments created during the French Revolution on 4 March 1790...

, France

France

The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...

; from various marble quarries near Seravezza, Tuscany

Tuscany

Tuscany is a region in Italy. It has an area of about 23,000 square kilometres and a population of about 3.75 million inhabitants. The regional capital is Florence ....

, Italy

Italy

Italy , officially the Italian Republic languages]] under the European Charter for Regional or Minority Languages. In each of these, Italy's official name is as follows:;;;;;;;;), is a unitary parliamentary republic in South-Central Europe. To the north it borders France, Switzerland, Austria and...

; a marble quarry in Valais

Valais

The Valais is one of the 26 cantons of Switzerland in the southwestern part of the country, around the valley of the Rhône from its headwaters to Lake Geneva, separating the Pennine Alps from the Bernese Alps. The canton is one of the drier parts of Switzerland in its central Rhône valley...

, Switzerland

Switzerland

Switzerland name of one of the Swiss cantons. ; ; ; or ), in its full name the Swiss Confederation , is a federal republic consisting of 26 cantons, with Bern as the seat of the federal authorities. The country is situated in Western Europe,Or Central Europe depending on the definition....

 and from Khaydarkan, Fergana Valley

Fergana Valley

The Fergana Valley or Farghana Valley is a region in Central Asia spreading across eastern Uzbekistan, Kyrgyzstan and Tajikistan. Divided across three subdivisions of the former Soviet Union, the valley is ethnically diverse, and in the early 21st century was the scene of ethnic conflict...

, Alai Mountains, Kyrgyzstan

Kyrgyzstan

Kyrgyzstan , officially the Kyrgyz Republic is one of the world's six independent Turkic states . Located in Central Asia, landlocked and mountainous, Kyrgyzstan is bordered by Kazakhstan to the north, Uzbekistan to the west, Tajikistan to the southwest and China to the east...

.

External links

• Discovery of guettardite in French