Yes, Rosso Matisse Semiprecious Stone can be used in exterior applications in very sunny climates. This stone is typically durable and resistant to UV radiation, making it suitable for outdoor use. However, it is still recommended to consult with a stone professional or supplier to ensure that the specific product and its finish are suitable for your intended application and climate. They can provide proper guidance based on the specific characteristics of Rosso Matisse Semiprecious Stone and your project requirements.