A jewelry-store owner who had just returned from vacation was shot during a stickup at his Brooklyn shop yesterday, authorities said.

Two thugs stormed into Studio Jewelry, on Nassau Avenue in Greenpoint, at 12:50 p.m. and announced a robbery, cops said.

The owner, identified as Reggie Sanocki, 54, by his son, David, was shot in the stomach as the robbers smashed a glass display case, pocketed the jewels and fled, sources said.

Sanocki was in stable condition at Bellevue Hospital last night, and the robbers were still at large, the sources said made.