Yes, Italys Deep Grey Basalt can be used in exterior applications in cold climates. Basalt is a dense and durable volcanic rock that has excellent thermal properties, making it resistant to freezing and thawing cycles. Its high compressive strength and low absorption rate also make it suitable for withstanding harsh weather conditions. However, it is important to consider the specific type and quality of the basalt, as well as the installation and maintenance methods used, to ensure its suitability for cold climates. Consulting with a professional architect or stone supplier would be advisable for specific project requirements.