Sold by piece by weight. Sizes may look similar depending on shape/thickness. Each Amazonite stone has been weighted. 

XS: 15g to <20g

SM: 20g to <25g

MD: 25g to <35g

LG: 35g to <45g

XL:  45g to 50g

Stones cranked up by Jay Essex and Diana R. Anaya (Dianimal)

Pictures taken both in natural and artificial lighting