Gabriel Andreoli, son of Emil (also Emile) Andreoli his wife Marie, was a French born chemist, but by 1881 the family resided in London. Emil Andreoli was an inventor of note, for example, he filed United States patents for the effective production of ozone by silent electric discharges (1891, 1896), an improved process of electrolysis (1895), and an apparatus for the electrodeposition of gold and silver (1895). In 1895 Emil and his son Gabriel, still residing in London, filed a patent in Britain and the United States for the electrolytic production of amalgams. It involved the formation of an amalgam from a concentrated sodium chloride solution and the coating of copper or other metal plates with mercury, for the recovery of gold or silver by amalgamation.
Gabriel Andreoli came to South Africa in April 1897 to work at the Rand Central Ore Reduction Company. He became a member of the Chemical and Metallurgical Society of South Africa (from 1902 the Chemical, Metallurgical and Mining Society of South Africa) that same year. By 1905 he was electrometallurgist and cyanide manager at Roodepoort Central Deep, Ltd. At that time he published "Notes on the gold of the Roodepoort district" in the Journal of the society (1904/5, Vol. 5).
Andreoli married the widow Annie Maria Louisa Henwood, born Tyzack. She died in 1945. They still resided in Johannesburg in 1923, but in 1929 emigrated to the United States and lived at Irvington, New Jersey.