Edge of the Rain by Beverley Harper

Hunger ached in her belly... the lioness slid forward as close as she dared. The little boy seconds away from death was two, maybe three years old. He was lost in the heat-soaked sand that was the Kalahari desert.
Toddler Alex Theron is miraculously rescued by a passing clan of Kalahari Bushmen. Over the ensuing years, the desert draws him back, for it hides a beautiful secret... diamonds.
But nothing comes easily from within this turbulent continent and before Alex can ever hope to realise his dreams he will lost his mind to love and fight a bitter enemy who will stop at nothing to destroy him.