Using lime wedges moisten the rims of six margarita or cocktail
glasses. Set aside limes for garnish. Sprinkle coarse sugar on a
plate; hold each glass upside down and dip rim into sugar. Set aside.
Discard remaining sugar on plate.
In a blender combine the lemonade concentrate and raspberries; cover
until blended. Press mixture through a fine meshed sieve; discard
seeds. Return raspberry mixture to blender; add ice, strawberries,
blueberries, sugar and tequila if desired. Cover and process until
Pour into prepared glasses. Garnish with reserved limes.