Black Pearl — Peter Tonkin

An incalculable fortune in conflict minerals lies on the bed of a lost lake. The lake lies in the middle of a jungle hardly changed since the age of the dinosaurs, while the jungle stands on the slope of an active volcano which has destroyed the only civilisation nearby. The volcano serves as a border between two warring central African nations. And an uncontrolled, murderous guerrilla army claims the territory for its own, using a combination of modern terrorist techniques and timeless black magic to keep strangers out. Richard Mariner is leading a team into the heart of it all, seeking the lake and the fortune it contains - his only clues a half-forgotten legend and a huge black pearl that is so much more than it seems...