Anyone who tells you gold is a commodity and a "safe haven" is a "charlatan at best" and "a liar at worst," newsletter publisher Dennis Gartman told advisors and other professional investors this morning at the annual Inside Commodities conference in New York City. There is also a reasonable chance they might be "a cheat," Gartman declared.

Gold is the "dumbest commodity" in history primarily because it is a currency, not a commodity, Gartman said. Commodities like coffee, copper, crude oil and sugar have practical uses; gold is used only in jewelry, which is hardly a necessity.

In contrast, Gartman has described copper as the commodity "with a Phd. in economics" because that industrial metal sometimes has an almost clairvoyant ability to signal directional shifts in the global economy.

Currencies are meant to be "traded one against another, [like] yen versus sterling," Gartman explained. Gold, in his view, is just another currency trading across computer screens.

"I'm not a gold bug. I don't like gold bugs," Gartman added. Apparently not.

Gartman disparaged gold mining companies as "black holes people throw money into" rarely to see it again. However, he offered some praise for State Street's giant GLD gold ETF, saying it was a "legitimate investment" and had at least democratized gold investing.

Some investors' concept of gold as a safe haven is ludicrous, according to Gartman. Silver as a safe haven is even more preposterous. The lone gold trade Gartman likes is buying gold in Japanese yen because he is convinced that Japan's effort to devalue its currency will be successful and the yen could fall to 150 against the dollar.

Safe havens don't rise and fall in price by 2% or 3% on a daily basis the way gold does. Silver frequently surges or swoons 5% "at will," Gartman added. If you want a safe haven, buy two-year Treasury notes.

Gartman also believes that the wave of increased crude oil and natural gas supply coming on stream in the next few years is showing up in the oil market, which looks like it is "topping out."

"There is plenty of $110 a barrel oil out there," he said. In the next five or ten years, we may find out "how much $50 or $60 a barrel oil is out there."

Gartman isn't worried that the bond market will get sick when the Fed ends QE and starts to wind down its balance sheet because everybody expects it. "Even my caddie knows it's coming," he said.