Jacques-Louis de Bournon
The French mineralogist who described the round grains and metal in fallen stones alongside Edward Howard in 1802.
Key facts
- Born
- 1751
- Died
- 1825
- Nationality
- French
- Field
- Mineralogist
Jacques-Louis, Comte de Bournon, was a French nobleman and mineral collector who fled the French Revolution and lived for many years in London. There he became one of the finest crystallographers of his day, describing many minerals in detail. The mineral bournonite, a sulphide of lead, copper and antimony, is named after him.
When Edward Howard began analysing stones said to have fallen from the sky, de Bournon examined the same samples by eye and under a lens. He picked out their parts one by one: tiny rounded globules set in a finer grey matrix, shiny grains of metal, and specks of a yellowish iron sulphide. He also noticed the thin black crust that covered each stone, which we now call fusion crust and know forms as the surface melts during the flight through the air.
The little round grains he described are what are now called chondrules, the frozen droplets of molten rock that give the chondrites their name. De Bournon was among the first to describe them, although their name came decades later.
His descriptions, published with Howard's chemical analyses in 1802, showed that stones from widely separated falls had the same structure as well as the same chemistry. After the fall of Napoleon, de Bournon returned to France and in 1814 became director of the royal mineral collection of King Louis XVIII.