Sold by piece by weight. Pictures were taken under natural lighting at different times that is why you'll notice some difference in color. For size reference you'll see a true to size cardboard bank card  placed next to the stones.
 
Sizes:
SM: 7-11g
MD: 15-20g
LG: 24-30g
XL: 35-40g
 
Stones cranked up by Jay Essex and Diana (Dianimal)