Elon Musk has offered a bounty of a million doge for anyone who can provide evidence that he or his family has ever owned an emerald mine.

The multibillionaire, who was born in South Africa, has long been dogged by rumours that he’s a nepo baby.

In fact, he was born into an upper-middle-class family in Pretoria. His mother, Maye, worked as a model and dietitian and his father, Errol, worked many jobs including as an engineer and property developer.

Several news reports, such as one in the New Yorker, state Errol had an interest in an emerald mine. But Musk disputes this.

Twitter account DogeDesigner wrote: “Elon Musk never owned an emerald mine. An open offer of 69.420 Doge to all the media outlets who are publishing false information. Send me proof of its existence & take your doge.”

And in response, Elon Musk wrote: “I will pay a million Dogecoin for proof of this mine’s existence!”

That amounts to about NZ$133,500. It’s small change for Musk, who has a net worth of about US$188b (NZ$298b), according to the Forbes real-time billionaire list, mostly through his shares in Tesla and SpaceX.

Last year he wrote: “He [Errol] didn’t own an emerald mine & I worked my way through college, ending up ~$100k in student debt. I couldn’t even afford a 2nd PC at Zip2, so programmed at night & website only worked during day. Where is this bs coming from?”

- Andrew Backhouse, news.com.au