This recipe would actually work well with any type of berry (Rasberry, Blueberry, etc)

Blackberry Margarita

½ C. Blackberries (or other berry)
2 oz. Freshly Squeezed Lime Juice
½ oz. Agave Nectar
3 oz. White Tequila
2 oz. Orange Liquor
Kosher Salt, Lime or Blackberries for Garnish if Desired

In a cocktail shaker add the blackberries and use the muddler to mash them.  Then add ice, lime juice, agave, tequila and orange liquor.  Shake well and strain using the fine mesh strainer into a margarita glass.  Garnish as desired.  Cheers!