Yes, Tikul Limestone from Mexico can be used in exterior applications in very sunny climates. It is a durable and dense limestone that is resistant to weathering and can withstand harsh weather conditions. However, it is recommended to use a sealer to protect the stone from water and UV rays, which can cause discoloration or fading over time. It is also important to choose the right finish for the limestone, such as a honed or brushed finish, to reduce surface reflectivity and increase slip resistance for outdoor use.