Swiss chemist · 1837–1911
Marc Delafontaine
Marc Delafontaine was one of the first to detect holmium, through its spectrum, in 1878.
How Holmium was found
Delafontaine studied erbium and related earths in Geneva. With Jacques-Louis Soret he found absorption lines in a sample from samarskite that did not belong to erbium or any known element. Soret called the cause “element X”.
A year later Per Teodor Cleve separated the new earth chemically and named it holmia. Delafontaine claimed several other new rare earths that turned out to be mixtures, a common problem in a field where elements were extremely hard to separate.
Shared the credit
The discovery is credited jointly to these scientists.
Life and career
Born 1837 · Died 1911
Delafontaine trained and worked in Geneva. He later moved to the United States and worked as a chemist in Chicago.
Discovered in the same era
Other elements identified within ten years of 1878.