Cook the swerve in the water on medium heat for 2-3 minutes or until the sugar is fully dissolved into the water. Let cool.
Put about 4 raspberries into eight glasses, then add in some fresh mint evenly distributed into each glass and a teaspoon of lime juice. Mash together lightly with a back of spoon to try to get the flavors to mix.
Fill the glasses with one ounce of rum, 2 tablespoons of the melted swerve-water combo and the rest with seltzer. Fill more with the lime slices and some fresh mint.