What is ironic in the book king solomons mines?

Below you will find two excerts from a fantastic article on the novel. I have included the link for you to follow in sources;

"King Solomon’s Mines was a window back into an old world that he had been consistently denied. By the time I was old enough to begin understanding such issues – the colonial ideal was dead. But he still believed in it. The idea was that more fortunate peoples owed it to the less fortunate to share in their success. For him, the motivating principle of colonialism was not greed, but ‘noblesse oblige’ – great power implies great responsibility. King Solomon’s Mines represented that best of British spirit to a popular culture that believed it through and through."

"The diamond mine itself is the title. But there is a cautionary dimension. As the novel relates, all those that seek the diamonds out of greed end up either failing miserably or perishing in some misadventure. Our protagonists are seeking the lost brother of Sir Henry. When they make it to the mine itself, it is only after they have performed noble deeds across the land of the Kukuanas (a fictional lost tribe of Zulu like warriors that live beyond an impassable desert). When they offer to go to war for their friend Umbopa, he offers them the treasures of Solomon as a reward for their help – but only Quatermain acknowledges that he would include this as his motive as he’s a “practical man???. Once the war is done, Haggard begins to create a sense of deep foreboding about the treasure. Gagool, the old witch that leads them to the treasure, makes repeated mention of the white man’s lust for white stones and juxtaposes that with the grizzly end that she predicts for them – as though it is their greed that will be their undoing. Indeed, after being trapped by Gagool in the cave of riches, they hardly care to take more than a handful – their near death experience causing them to regret their lust for limitless wealth."