The diamond industry has already been feeling the heat. Prices have slumped, Russian sanctions are threatening trade and the emergence of lab-grown gems is eating into some key traditional markets.

Now, the sector’s most dominant name is being cast adrift.

Anglo American on Tuesday said it will spin off or sell its De Beers business, ending an almost century-long relationship with the industry’s most famous name. The move, part of a wider restructuring to fend off a $43-billion approach from BHP Group, is a seismic shock for the diamond world.