Agate is a relatively common stone found in wide variety of types and markings.  This particular carving is made from orange red and yellow brown Agate from Brazil.  Agate is a grounding stone, said to be particularly useful in deep meditative practice to assist with self confidence and one's stability in the world; that is having a deeper understanding of one's place and value, irrespective of the goings on with other people.  Agate can be metaphorically akin to your supporting foundation stone in this respect.

The orange, red, yellow and brown tones in this earthly vibrant stone corresponds to the lower chakras governing our physical existence, including survival, personal security, reproduction, sex, our courage and self confidence; and as such is a useful stone for spiritual guidance regarding these areas of your life.  

Stone carved into the human skull form is a tool that can be used with meditative practice to expand your consciousness.