Was this clueless crook high?!

A UPS worker traded a whopping $160,000 diamond he stole for $20 worth of marijuana, ABC 15 in Phoenix reported.

Walter Earl Morrison, 20, was unloading a cargo plane at Sky Harbor Airport when he stuffed a package under his shirt – thinking it was a package of money, according to court documents.

When the half-baked bandit realized he had a pricey jewel in his possession, he traded it for the equivalent of about two joints before getting caught.

The diamond was eventually recovered and delivered to its intended owner, a UPS spokesperson said.

Morrison, of Phoenix, was charged last week with felony theft and subsequently fired from his job.