Preheat oven to 425. Butter a 9-inch-diameter circle in the center of a baking sheet.
In a large bowl, stir together the flour, sugar, baking powder, and salt. Cut the butter into 1/2-inch cubes and distribute them over the flour mixture. With a pastry blender or two knives used scissors fashion, cut in the butter until the mixture resembles coarse crumbs. In a small bowl, stir together the eggs, orange juice, vanilla and orange peel. Add the egg mixture to the flour mixture and stir to combine. The dough will be sticky. With lightly floured hands, knead in the chocolate chips until they are evenly distributed.
With lightly floured hands, pat the dough into an 8-inch-diameter circle in the center of the prepared baking sheet. If desired, brush the egg mixture over the top and sides of the dough. With a serrated knife, cut into 8 wedges. Bake for 18 to 20 minutes, or until a cake tester or toothpick inserted into the center of a scone comes out clean. Remove the baking sheet to a wire rack and cool for 10 minutes. With a spatula, transfer the scones to the wire rack to cool. Recut into wedges if necessary. Serve warm, or cool completely and store in an airtight container. These scones freeze well.