I do not have access to specific technical data regarding the performance of Steinsvik Quartzite in sunlight. However, general quartzite usage suggests that it is one of the strongest and most durable natural stones, able to withstand exposure and harsh weather conditions. Despite this, it is always best to verify the suitability of a material for a specific project through comprehensive testing prior to installation. Consult with a qualified stone installer or manufacturer for more information about the performance of Steinsvik Quartzite in exterior applications.