The Diamond Hunters - Wilbur Smith

The Van Der Byl Diamond Company, willed by its founder to his son Benedict, daughter Tracey and estranged foster-child Johnny Lance, turns out to be a bequest not of love, but of hatred. For it is couched in such terms as to offer Benedict an instrument of destruction of his bitterest rival. 'Destroy Johnny' was the old man's implacable message to his son, and, obsessively jealous of his foster-brother, Benedict sets out in ruthless pursuit of this goal.