*Jay Z is reportedly considering a pricey blue diamond to give Beyonce for their fourth wedding anniversary, in tribute to their daughter Blue Ivy Carter.

Paps caught the rapper leaving Jacob & Co. jewelry store in New York City, and a witness told the paper that he had been looking at the Lumina line of rare blue diamonds.

The source said, “I know he checked out colored diamonds, the rare blue ‘Lumina’ in particular.”

Jay Z was photographed (above) leaving the store and shaking the owner’s hand, then posing for pictures with local construction workers before jetting off in a tinted SUV.

Below, the latest paps pic of Beyonce and Blue.