A couple of urban island-dwellers have found buried treasure in their backyard — but so far the pirates are nowhere in sight.

WCBS says a safe containing about $52,000 worth of property — including diamonds, gold, jade and soaking wet cash — has been uncovered on Staten Island.

Matthew and Maria Colonna Emanuel always thought the rusting hulk of metal jutting out beneath some trees was just a cable box.

They were having some trees replaced when the mystery unfolded. The safe also held a paper with an address.

Matthew Emanuel knocked on their neighbor's door and asked if they'd ever been burglarized.

Bingo. The police report dates to 2011.

Maria Colonna Emanuel says there was never a question about returning the loot.

She says simply: "It wasn't ours."