In a medium-sized mixing bowl, whisk together the first six ingredients, then cut in the butter, using a pastry blender, fork, your fingers or a mixer. Add ground ginger, crystalized ginger, dates, and tangerine oil, stirring to combine. Stir in the sour cream or yogurt, then enough water to make the dough cohesive. Pat or roll the dough into two 3/4-inch-thick circles, or a 3/4-inch-thick square. Cut each circle into six pie-shaped wedges; or cut the square into 1 1/2- to 2-inch squares or circles. Place the scones on lightly greased or parchment-lined baking sheets (the circles should be left intact, with the wedges separated just a bit), and bake them in a preheated 425°F oven for 15 to 18 minutes, or until they're a light, golden brown.