In a bowl of a standing mixer fitted with paddle attachment stir together flour, granulated sugar, baking powder, baking soda, and salt. Add butter and zest and beat until mixture resembles coarse meal. Beat in currants. In a bowl whisk together buttermilk and eggs and add to flour mixture, beating just until a dough forms.
Preheat oven to 350°F. and line 2 baking sheets with parchment paper. On each sheet arrange six 1/2-cup mounds of dough about 1 inch apart. Sprinkle mounds with raw sugar and chill 15 minutes.
Bake scones in upper and lower thirds of oven, switching position of sheets half-way through baking, until light brown, about 20 minutes.
* Available from Suttons Bay Trading Company