Abraham de Jong, born in Amsterdam on 9 October 1878, was a son of Philip Mozes de Jong and Klaartje Bartels. When Abraham was 20 years old, he became a member of the ANDB, the General Dutch Diamond Workers' Union, where he was trained in rose- and brilliant polishing. His first membership started on 1 January 1898 as a brilliant polisher’s assistant in section 2.
On 18 August 1910, Abraham de Jo…