You are looking at an amethyst druse skull. The skull is 9.9 inches long from front to back.

The stone of spirituality and dream recall . Used for contentment and meditation. Provides common sense and flexibility in decisions. Strengthens and enhances psychic abilities, imagery and mind quieting. Wear when sleeping or when awake to reduce anger, impatience, and nightmares. Most effective on the Brow and Crown Chakra. Amethyst contains the grounding color of red with the energy of blue, which is expanding, spacious and flow of peace. Amethyst is the color that you see in the sky as twilight transitions into night. Amethyst takes you on this transition from the magic time of dusk to a conscious shift into a different place. Crossing this threshold is the lesson of humility , which Amethyst can teach us. This stone can show us how to let go and trust; surrender so that you may see beyond the cycle that consumes your attention; give it all up, so that you can receive more; and bow, that you may become a part of the greater whole. Amethyst is considered a Master Healing stone.