Yes, United Statess Desert Grey Calcarenite can be used outdoors. Calcarenite is a type of limestone composed of smaller grains of sediment which are cemented together. It is a durable and weather-resistant material that can withstand outdoor conditions. Calcarenite is often used for various outdoor applications such as exterior cladding, paving, landscaping, and outdoor sculptures. However, it is always recommended to consult with a professional or supplier to ensure the specific calcarenite material is suitable for the intended outdoor use and is properly maintained over time.