Police were called to the station at 4191 First St. at 8:10 p.m. The clerk at the Union 76 gas station said that the robber entered the store and showed the clerk a black semi-automatic handgun and demanded cash.
The robber fled towards Vineyard Avenue, and police checked the area but did not locate any suspects.
Police are searching for a light-skinned male in his early 20s, between 5 feet 7 inches and 5 feet 9 inches tall, weighing 140 pounds. He was wearing a dark-colored long-sleeve shirt under a white T-shirt, dark-colored basketball-style shorts with white stripes down the side, black shoes and a black beanie.
He obscured his face with a black bandana and carried a gray pinstriped backpack, police said.