Bitcoin hit another record Monday, but commodities whiz Dennis Gartman still isn't buying.

"It is a punter's dream," Gartman told CNBC's "Fast Money." "I give them credit for that, but it is something that I will absolutely stay away from, have stayed away from it, didn't understand it to begin with, don't understand it now."

Gartman said he appreciates bitcoin's introduction of blockchain technology. However, the cryptocurrency's price fluctuates too much to convince him to invest.

"What bothers me is that something that can move 5, 10, 15, 18 percent in the course of the day for what's supposed to be a pricing mechanism," Gartman said. "How can you buy a house? How can you buy a car? How can you buy Starbucks with bitcoin when the price is going to fluctuate as [dramatically] as it has?"

When bitcoin was introduced, it was supposed to be better than common currencies like the dollar or euro because it was supposed to be finite, Gartman said. Now, it's become an infinite currency, he said, and that's a big problem.

"We'll walk in one day and this will all have ended," he said. "And it will end very badly."