René-Just Haüy, also Abbé Haüy

He was born in Saint-Just-en-Chaussée an der Oise. † June 3, 1822, in Paris

He was a French mineralogism. The mineral Haüyn is named after him.

In 1804 he was elected a member of the Royal Prussian Academy of Sciences; He was an honorary member from 1812.

In 1809 he became a corresponding member of the Royal Dutch Academy of Sciences and in 1818 a member of the Royal Society. He was an honorary member of the Russian Academy of Sciences in St. Petersburg and the Royal Society of Edinburgh.

Haüy described the law of symmetry of crystallography. He dropped a crystal of lime spar to the ground and discovered that the fragments have the same shape as the original crystal. From this he concluded that crystals are made up of smaller units that have the same shape as the crystal itself. Integrating molecules. he called these smaller units.

René-Just Haüy with Goniometer

From this experiment of 1784 follows the law of rational indices, according to which each crystal surface can be described by three (usually small) whole numbers. This law applies to almost all crystals except aperiodic crystals. In addition, he made discoveries about pyroelectricity.

Haüy is immortalized on the Eiffel Tower. It can be found under 72 names on the Eiffel Tower.