Alfred Louis Olivier Legrand Des Cloizeaux (October 17, 1817 – May 6, 1897) was a French

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...

 mineralogist.

Des Cloizeaux was born at Beauvais

Beauvais

Beauvais is a city approximately by highway north of central Paris, in the northern French region of Picardie. It currently has a population of over 60,000 inhabitants.- History :...

, in the department of Oise

Oise

Oise is a department in the north of France. It is named after the river Oise.-History:Oise is one of the original 83 departments created during the French Revolution on March 4, 1790...

. He studied with Jean-Baptiste Biot

Jean-Baptiste Biot

Jean-Baptiste Biot was a French physicist, astronomer, and mathematician who established the reality of meteorites, made an early balloon flight, and studied the polarization of light.- Biography :...

 at the Collège de France

Collège de France

The Collège de France is a higher education and research establishment located in Paris, France, in the 5th arrondissement, or Latin Quarter, across the street from the historical campus of La Sorbonne at the intersection of Rue Saint-Jacques and Rue des Écoles...

. He became professor of mineralogy at the École Normale Supérieure

École Normale Supérieure

The École normale supérieure is one of the most prestigious French grandes écoles...

 and afterwards at the Muséum National d'Histoire Naturelle

Muséum national d'histoire naturelle

The Muséum national d'Histoire naturelle is the National Museum of Natural History in Paris, France.- History :The museum was formally founded on 10 June 1793, during the French Revolution...

 in Paris

Paris

Paris is the capital and largest city in France, situated on the river Seine, in northern France, at the heart of the Île-de-France region...

. He studied the geyser

Geyser

A geyser is a spring characterized by intermittent discharge of water ejected turbulently and accompanied by a vapour phase . The word geyser comes from Geysir, the name of an erupting spring at Haukadalur, Iceland; that name, in turn, comes from the Icelandic verb geysa, "to gush", the verb...

s of Iceland

Iceland

Iceland , described as the Republic of Iceland, is a Nordic and European island country in the North Atlantic Ocean, on the Mid-Atlantic Ridge. Iceland also refers to the main island of the country, which contains almost all the population and almost all the land area. The country has a population...

, and wrote also on the classification of some of the eruptive rocks; but his main work consisted in the systematic examination of the crystal

Crystal

A crystal or crystalline solid is a solid material whose constituent atoms, molecules, or ions are arranged in an orderly repeating pattern extending in all three spatial dimensions. The scientific study of crystals and crystal formation is known as crystallography...

s of numerous minerals, in researches on their optical

Optics

Optics is the branch of physics which involves the behavior and properties of light, including its interactions with matter and the construction of instruments that use or detect it. Optics usually describes the behavior of visible, ultraviolet, and infrared light...

 properties and on the subject of light polarization. He wrote especially on the means of determining the different feldspar

Feldspar

Feldspars are a group of rock-forming tectosilicate minerals which make up as much as 60% of the Earth's crust....

s.

Des Cloizeaux was elected as a member of the French Academy of Sciences

French Academy of Sciences

The French Academy of Sciences is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French scientific research...

 in 1869, and was its President in 1889. He was awarded the Wollaston Medal

Wollaston Medal

The Wollaston Medal is a scientific award for geology, the highest award granted by the Geological Society of London.The medal is named after William Hyde Wollaston, and was first awarded in 1831...

 by the Geological Society of London

Geological Society of London

The Geological Society of London is a learned society based in the United Kingdom with the aim of "investigating the mineral structure of the Earth"...

in 1886. His best-known books are Leçons de cristallographie (1861) and Manuel de minéralogie (2 vols., Paris, 1862, 1874 and 1893).