Sailor's Thirsty Desire
This thumb sized crystal is enchanted to instantly distill fresh water from either saltwater or an impure source. The effect emulates the work of evaporation, which will remove almost all sizeable contaminants and salt on up to 1000 gallons of water (or whatever barrel or container it is dropped into). To be effective the user must succeed a moderate Finesse check vs 9. Crystal grants the lab total a +5 bonus.
Rego Aquam 5 (Base 3 to change water to steam, +1 capture and move back, +1 Touch)
Note - could be argued that the base needs to be higher if the water-steam-water process was too volatile, so I added an extra mag. Might need another, I’m not sure.