Sunstone Metals (ASX:STM) is a mineral exploration company with high-quality gold and copper assets in Ecuador. Sunstone's flagship project is the Bramaderos Gold-Copper Project in southern Ecuador, a joint venture with TSXV-listed Cornerstone Capital Resources. Sunstone can earn up to an 80% interest in the project by funding activities through a decision to mine. The project is considered to be highly prospective for the discovery of porphyry and epithermal gold-copper deposits.