Yes, Crystal Quartz can be used outdoors as it is a hard and durable stone. It is resistant to weathering and does not easily fade or deteriorate in the sun or rain. Crystal Quartz is often used for outdoor applications like walkways, countertops, landscape features, and decorative elements. However, it is important to note that prolonged exposure to extreme temperatures and direct sunlight may cause slight discoloration or fading over time. Additionally, installation and maintenance should be done properly to ensure the stones longevity and appearance.