Yes, Italys Seiser Basalt can be used in exterior applications in very humid climates. Basalt is a type of volcanic rock that is known for its durability and resistance to weathering. It has low water absorption properties and is resistant to moisture, making it an ideal material for humid climates. Additionally, Seiser Basalt is specifically sourced from the Seiser Alm region in Italy, which means it is already being used in local exterior applications where the climate can be humid. It is always recommended to consult with a local expert or professional to ensure that the specific project requirements are met.