You are purchasing one skull. You will need a black light for these crystals to glow. 
Yooperlite Healing Properties:
Yooperlite is said to help with a wide variety of issues, including stress relief, anxiety, and depression. It is also said to improve sleep quality, increase energy levels, and boost the immune system. Yooperlite is a very versatile crystal that can be used in many different ways. It is said to have metaphysical properties that can help to promote clarity and understanding, as well as aiding in the ability to see the truth. Yooperlite can also help to provide strength during times of change or upheaval.