Tempest Stone 
Energized and dreamy pietersite cabochon in fine and sterling silver bezel setting on hammered sterling silver double wire cuff bracelet.
Pietersite is also known as Tempest Stone as it is a stone that carries a charge, a little like a storm raging within it. 
It's action to utilize the power of your imagination to dream and to create beautiful visions and ideals is very powerful.
Pietersite is a trade name for a dark blue-grey breccia aggregate made up mainly of hawk's eye and tigereye. It is a variety of chalcedony (itself a variety of quartz) with embedded fibers of amphibole minerals in varying degrees of alteration. The fibers cause a blue chatoyancy like that seen in tigereye.