Jean-Baptiste L. Romé de l'Isle

{{Short description|French geologist (1736–1790)}}

Image:Romé de L'Isle01.jpg]]

Jean-Baptiste Louis Romé de l'Isle (26 August 1736 – 3 July 1790) was a French mineralogist, considered one of the creators of modern crystallography.

Romé was born in Gray, Haute-Saône, in eastern France. As secretary of a company of artillery in the Carnatic Wars he visited the East Indies, was taken prisoner by the English in 1761, and held in captivity for several years.{{EB1911|inline=y|wstitle=Romé de l'Isle, Jean Baptiste Louis|volume=23|page=685}} He was also an alumnus of the Collège Sainte-Barbe in Paris.

Subsequently, he became distinguished for his researches on mineralogy and crystallography. He was the author of Essai de Cristallographie (1772), the second edition of which, regarded as his principal work, was published as Cristallographie (3 vols. and atlas, 1783).{{cite book|title=Cristallographie |edition=2|year=1783|publisher=Imprimerie de Monsieur |url=https://catalog.hathitrust.org/Record/001035389?|postscript=; 4 vols. with atlas as 4th vol.}} His formulation of the law of constancy of interfacial angles built on observations by the geologist Nicolaus Steno.{{Citation needed|date=March 2024}}

In 1775, he was elected a foreign member of the Royal Swedish Academy of Sciences. He died in Paris, France on 3 July 1790.

File:Rome de l'Isle, Jean Baptiste Louis de – Cristallographie, 1783 – BEIC 11981083.jpg