You are looking at an Amethyst skull. The skull is 6 inches from top to bottom.

Amethyst is a purple to pale violet variety of crystalline quartz and is usually transparent or translucent. The colour is due to the iron compounds present. It is also a diachronic, showing a blue or reddish purple tinge when viewed from different angles. It usually has distinctive inclusions which can look like tiger stripes, thumb prints or feathers. Amethyst has a direct link to the mind. It bolsters the production of the hormones, and strengthens the cleansing organs, the circulatory system and blood, the immune system, and body metabolism. It soothes the nervous system and assists in the transmission of neural signals. It helps you feel less scattered and more in control of your faculties. Memory skills and motivation improve. Goals are clearer, more realistic, and easier to achieve.