Zabargad Island (Egyptian Arabic: جزيرة الزبرجد Geziret El Zabargad, also known as St. John's Island in English) is the largest of a group of islands in Foul Bay, Egypt. It covers an area of 4.50 square kilometres (1.74 square miles). It is not a Quaternary volcanic island, but rather is believed to be an upthrust part of upper mantle material. The nearest island is known as "Rocky Island". The island is slightly north of the Tropic of Cancer, and its highest point is 235 metres (771 feet).