The Square Jewel is a quest item from The Legend of Zelda: Oracle of Seasons. This blue jewel can be found within a chest inside a bombable cave south of Poison Moth's Lair at coordinate 13 ,C. This cave is only accessible in the wintertime and after Link has obtained the Bombs and Shovel. This jewel, along with the Round Jewel, Pyramid Jewel, and X-Shaped Jewel, is required to gain access to the Tarm Ruins.
In a Linked Game, the Square Jewel is found in a cave in the northwest Eyeglass Lake at coordinate 11 ,H. Link must first change the season to summer to drain the lake, thus allowing access to the cave.
Though the Treasure Map is useful in finding the Square Jewel, it is still possible to obtain it without the map.