Sold by piece by weight. Sizes may look similar depending on shape/thickness.
Most pieces have a flat side.
Each Labradorite stone has been weighted. 
SM: 15g to <20g
MD: 20g to <30g
LG: 30g to <40g
XL:  40g to 50g
Stones cranked up by Jay Essex and Diana R. Anaya (Dianimal)
Pictures taken both in natural and artificial lighting