Bitcoin's velocity is a sign that its surge is "parabolic," and that could mean the cryptocurrency's rally won't last, CNBC's Jim Cramer said Wednesday.

Cramer spoke moments after the digital currency spiked through $11,000, according to industry site CoinDesk, hours after surpassing the $10,000 level for the first time. Bitcoin has surged more than 1,000 percent this year.

"Even if you believe in bitcoin, the velocity of the move is a sign that it is parabolic. And parabolic moves don't last," Cramer said on "Squawk on the Street."

"And I know that when I look at that, I say to myself, 'OK, if I owned it, what would I really be doing?'" Cramer added. "And the answer is when you have that big of gain you have to take some profits. That velocity is crazy."

Cramer's comments on bitcoin resembled that of closely followed trader Art Cashin. Cashin, UBS director of floor operations at the New York Stock Exchange, said Monday that the cryptocurrency has reached "parabolic" levels, and the cryptocurrency has some at the Federal Reserve worried.

"I think we're in the fear-of-missing-out phase now," Cashin said on "Squawk on the Street." "I think initially there was some concern. I am told — and take this with a huge grain of salt — that the movement is even beginning to worry some people in the Federal Reserve."

Earlier Wednesday, William Dudley, president and CEO of the Federal Reserve Bank of New York, said the Fed is exploring the idea of its own digital currency, according to Dow Jones.

Bitcoin has risen as exchanges such as the CME Group and Cboe Options announced plans to launch futures contracts for the currency.

—CNBC's Evelyn Cheng and Reuters contributed to this report.