Mineral crystallization is an equilibrium process. The same fluids from which a crystal is formed can also dissolve that crystal. Here we have a light green, opaque to transparent (even gemmy in parts)  beryl crystal which has been naturally corroded, leaving one full crystal face in tact. Unusual locality for an etched beryl - especially of this size; the majority of etched beryls come from Minas Gerais, Brazil. I consider crystal etching to be a specimen enhancement (it illustrates important geological and mineralogical phenomena) instead of damage; this example is in fine condition.