Sunstone Island

Sunstone Island is an island appearing in Dragons: Defenders of Berk, and is also location searchable by Toothless in the game, Dragons: Rise of Berk.

Geography
According to the image of Sunstone Island on Hiccup's Race to the Edge map, it has much vegetation and perhaps large old trees, based on the single tree stylized on the map image.

Dragons: Defenders of Berk
In "Appetite for Destruction", the Dragon Riders survey dragon populations on several islands. The Riders have marked the dragons of Sunstone Island with orange paint. As the Riders each mark dragons, they realize that dragons from one island are ending up on the others. They discover that these islands are being systematically destroyed and the dragon populations are migrating. A Screaming Death is responsible, destroying islands as it makes its way to Berk.

Other Appearances
Sunstone Island does appear on the Interactive Map on the Dragons: Race To the Edge website. However, no special description is given.

Trivia

 * Historically, there is an as-yet unproven theory that Vikings used sunstones to help navigate their longships. Sunstone is a mineral that is able to polarize light, so in theory a Viking at sea could look through the stone and find out where the Sun was located on a cloudy day.