Jasper

Jasper is a variety of Chalcedony, which is a microcrystalline variety of Quartz.

and for those into crystals:

Jasper is known as the “supreme nurturer”. It sustains and supports through times of stress, and brings tranquility and wholeness. Jasper provides protection and absorbs negative energy. It balances yin and yang. Jasper clears electromagnetic and environmental pollution, including radiation. It encourages honesty with one's self. Provides courage to assertively tackle problems. Aids quick-thinking and promotes organisational abilities. Jasper stimulates the imagination and transforms ideas into action.