Fil two highball glasses with ice.
Squeeze the 8 raspberries in your fingers and put 4 in each glass.
Squeeze the 6 blackberries in your fingers and put 3 in each glass.
Pour 1-1/2 ounce of gin into each glass.
Squeeze 1/2 of the lemon juice into each glass.
Top with the tonic water.
Garnish with a lemon slice and a mint sprig.