We have sometimes spherical crystals on stock which are in the optimal size range for the emitters. The size varies between 3.5"-4.2". We don not sell individual crystals, only selling them  form our sortiment on a flat rate.  We suggest this option for those who does not want to look for appropiate crystals on their own just want grab one which is right in size and type for the emtters. 
 
Note: The image is only illustration! If you purchase a crystal we randomly pick one from our sortiment and deliver to you.