Puree blueberries, cherries and mint leaves until smooth, pour in a large bowl.
Sprinkle the packets of unflavored gelatin over the mixture, let stand 1 minute.
Heat water to a boil.
Pour boiling water over the mix and gelatin, mix until gelatin is completely dissolved, approximately five minutes.
Pour into silicone molds and refrigerate 3 to 4 hours, or overnight if possible.