This is a polished sphere made from K2 granite, which is also known as K2 Jasper or "raindrop azurite". 
K2 granite is a stone consisting of white or gray granite with small, blue spherical formations of azurite. 
The stone is mined from the base of K2, the second-highest mountain in the world, located near the border of Pakistan and China. 
It is a rare and unusual material, as it is uncommon to find a copper mineral like azurite in a granite rock. 
The blue spots of azurite can range from a few millimeters to about two centimeters in diameter.