Stocks tied to cryptocurrencies such as Advanced Micro Devices (AMD) - Get Report and Nvidia (NVDA) - Get Report have been on fire due to the rise in the underlying asset, until now

Cryptocurrencies have been crashing after hitting all-time highs, although leading virtual currency bitcoin has been holding up better than that rest. But, to well-known investor Doug Casey, they are just speculative vehicles.

"You have to consider them like penny stocks and treat them that way," he said in the last part of a three-part interview with Kitco News. 'You can't buy them now and look at them as a store of value because they are not.'

Despite a pullback, bitcoin is still up on the year, up over 100% since January, according to Kitco's aggregated charts. However, the well-known gold bug is not convinced. "Just like penny stocks, most of them are burning matches. I think you hold onto them long enough, you will get burned."

This story comes via www.kitco.com

Watch more from Kitco News: