You are looking at a ruby zoisite skull. The skull is 3.1 inches long, from front to back.

Green and black, often with red streaks of ruby. For trust in the universe, releasing fears. Strengthens heart, energy/adrenals and reproductive Chakra. General health. This stone can be used to dispel laziness and idleness. It is often used in treating disorders of the middle and upper jaios in Chinese Medicine, considered the heart, spleen, stomach, pancreas and lungs. When Zoisite is shared with ruby in it's matrix, it shares the same metaphysical properties of both stones. When this stone is found in the colors of the upper Chakra, clear, blue, purple, violet, it is considered the rare stone, Tanzanite.