White balls of Gyrolite are locked together to create the appearance of stacked snowballs. Randomly growing out of the stacks are white crystals of Stilbite and clear crystals of Apophyllite. On average the Gyrolite balls are 20mm, the Apophyllites range from 15-20 mm and the Stilbites are small, usuall less than 8 mm. Size cm (HxWxD): 8x5x5