Heat oven to 425 degrees F. Grease large baking sheet.
In a large bowl, combine flour, 2 tablespoons sugar, baking powder, salt, and cream of tartar. With pastry blender or 2 knives, cut in butter until mixture resembles coarse crumbs.
Separate egg, placing the egg white in a cup and the yolk in a small bowl. Beat egg yolk with a fork and stir in half-and-half. Add yolk mixture to dry ingredients and mix lightly with a fork until mixture clings together and forms a soft dough.
Turn dough out onto lightly floured surface and knead gently 5 or 6 times. Gently fold in blueberries. Divide dough in half. With a lightly floured rolling pin, roll one half of dough into a 7-inch round. Cut into 4 wedges. Repeat with remaining half of dough.
Place scones 1 inch apart on greased baking sheet. Pierce tops with tines of fork. Brush with reserved egg white . Sprinkle with remaining 1 tablespoon sugar.
Bake scones for 15 to 18 minutes when using fresh blueberries or about 20 minutes when using frozen - or until golden brown. Serve warm.