Porphyry Island is the last island in a chain stretching southwest from the Black Bay Peninsula. It is generally flat to rolling with little relief and the rugged shoreline offers little shelter. The rocks of the peninsula and the island are of Late Precambrian age and consist of more than 300 distinctive lava flows. This nature reserve is managed to protect its significant biological and geological values. There are no visitor facilities and the islands remote location makes visitation difficult. The unauthorized collection of rare plants and other natural objects from the nature reserve is prohibited. Anyone wishing to conduct scientific research must obtain an approved research application.