Gabriel Delafosse (16 April 1796 – 13 October 1878) was a French

mineralogist Mineralogy is a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the proces ...

who worked at the Natural History Museum in Paris and for sometime at the University of Paris. He contributed to development of the idea of

unit cell In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...

s in crystallography. The mineral Delafossite is named after him. He was one of the founding members of the Société Geologique de France.

Biography

Delafosse was born in Saint-Quentin, the son of a magistrate. He was educated locally and at Rheims before joining the École Normal Supérieure and then went to work at the Museum of Natural History from 1816 under

René Just Haüy René Just Haüy () FRS MWS FRSE (28 February 1743 – 1 June 1822) was a French priest and mineralogist, commonly styled the Abbé Haüy after he was made an honorary canon of Notre Dame. Due to his innovative work on crystal structure and hi ...

. After Haüy's death he published posthumously some notes on

crystallography Crystallography is the experimental science of determining the arrangement of atoms in crystalline solids. Crystallography is a fundamental subject in the fields of materials science and solid-state physics (condensed matter physics). The wor ...

and mineralogy in volumes of ''Traité de minéralogie'' (1822-1823). He defended his thesis in crystallography on hemihedry (hemihedral shape of a crystal) in 1840. He was an assistant was the chair of mineralogy at the Mineralogy Laboratory of the

National Museum of Natural History The National Museum of Natural History is a natural history museum administered by the Smithsonian Institution, located on the National Mall in Washington, D.C., United States. It has free admission and is open 364 days a year. In 2021, with 7 ...

in Paris, in 1857, then joined the Faculty of Science from 1822, teaching at the École Normale Supérieure from 1826, becoming a professor in 1841 and working until 1876. Delafosse was a founding member of the Société Geologique de France. Delafosse showed that one had to distinguish the "integrating molecule" of Haüy from the chemical molecule. He proposed the concept of " maille" (

Unit cell In geometry, biology, mineralogy and solid state physics, a unit cell is a repeating unit formed by the vectors spanning the points of a lattice. Despite its suggestive name, the unit cell (unlike a unit vector, for example) does not necessaril ...

) in crystallography. In line with his works are those of his student

Louis Pasteur Louis Pasteur (, ; 27 December 1822 – 28 September 1895) was a French chemist and microbiologist renowned for his discoveries of the principles of vaccination, microbial fermentation and pasteurization, the latter of which was named afte ...

on molecular dissymmetry. A mineral species was dedicated to him by

Charles Friedel Charles Friedel (; 12 March 1832 – 20 April 1899) was a French chemist and Mineralogy, mineralogist. Life A native of Strasbourg, France, he was a student of Louis Pasteur at the University of Paris, Sorbonne. In 1876, he became a professor of ...

in 1873, the delafossite, composed of copper and iron oxide.Friedel (1873), Comptes Rendus de l'Académie des Sciences de Paris, 77:211.

Publications

*''Précis élémentaire d'histoire naturelle'', Hachette, 1833. * ''De la structure des cristaux, considérés comme base de la distinction et de la classification des systèmes cristallins. Sur l'importance de l'étude de la symétrie dans les différentes branches de l'Histoire naturelle, et en particulier dans la morphologie végétale et animale'', ''Thèse de sciences'', Université de Paris, 1840. * ''Recherches sur la cristallisation considérée sous les rapports physiques et mathématiques'', in ''Mémoires de l'Académie des sciences de Paris, tome viii des savants étrangers'', 1843. * ''Nouveau cours de minéralogie'', 1858. * ''Rapport sur les progrès de la minéralogie'', in ''Recueil de rapports sur les progrès des lettres et des sciences en France'', Paris, 1867. (According to F. Dagognet, ''Méthodes et doctrine dans l'œuvre de Pasteur'', Paris, 1967, reprinted under the title ''Pasteur sans la légende'', 1994, p. 57, n. 2, this report includes a luminous exposition of the '"History of crystallography and its problems".) ;In collaboration * Bulletin des sciences naturelles et de géologie * Bulletin universel des sciences et de l'industrie * Historiæ naturalis: libri XXXVII

Bibliography

* François Dagognet, ''Méthodes et doctrine dans l'œuvre de Pasteur'', Paris, 1967, reprined. under the title ''Pasteur sans la légende'', 1994, p. 25-144, passim. * Henk Kubbinga (dir.), ''L'histoire du concept de « molécule »'', t. 3, Springer, 2001, passim. (Partiall
online
) * Philippe Jaussaud and Édouard-Raoul Brygoo, ''Du Jardin au Muséum en 516 biographies'', Publications scientifiques du Muséum, biography of Gabriel Delafosse
online

Notes and references

{{DEFAULTSORT:Delafosse, Gabriel French mineralogists 1796 births 1878 deaths