Sold by piece by weight.
Sizes may look similar depending on shape/thickness.
Pictures taken both in natural and artificial lighting
Each Ocean Jasper stone has been weighted. 
SM: 5+ to 10g
MD: 10+ to 15g
LG: 15+ to 20g
XL: 20+ to 25g
Stones cranked up by Jay Essex and Diana R. Anaya (Dianimal)