Use a 1-quart saucepan and mix gelatin and sugar. Stir in 1/2 cup cranberry juice; let stand 3 minutes to soften gelatin. Stir over low heat until gelatin completely dissolves, (about 3 minutes). Remove from heat.
In a 2-cup glass measuring cup, combine tea bags with boiling water, let steep 5 minutes. Remove tea bags and discard.
In a medium bowl, stir together dissolved gelatin, tea and remaining 1 1/2 cups juice. Refrigerate juice mixture, stirring occasionally, until it has the consistency of unbeaten egg whites, (about 1 hour and 45 minutes). To quick-chill gelatin, set bowl in larger bowl of ice water and stir frequently with rubber spatula just until mixture begins to thicken.
Stir raspberries and cantaloupe into thickened gelatin; pour into 5-cup mold. Cover and refrigerate until firm, 4 hours.
To un-mold gelatin, place mold up to rim in bowl of warm water for a few seconds. Be careful not to melt gelatin. Remove mold from water. Insert small metal spatula around edge of mold to release gelatin. Dry outside of mold. Invert platter on top of mold, then quickly invert mold and platter together. Lift off mold. Garnish with mint, raspberries and cantaloupe.