Preheat the oven to 425 F. Line a baking sheet with parchment or a silpat for easier cleanup. Sift together the rice flour, Clabber Girl Cornstarch, tapioca starch, guar or xanthan gum, Clabber Girl Baking Powder, baking soda, cinnamon and salt. Stir in the sugar and make a well in the center. Whisk together the melted butter, half-n-half and the egg. Pour into the dry mixture and add the blueberries. Mix gently with a wooden spoon to combine. Mixture may be quite sticky – let sit for a few minutes to solidify somewhat. Drop the batter into 12 even portions on the prepared baking sheet. (An ice cream scoop helps make even portions). Sprinkle the tops with additional sugar for a shiny appearance. Bake for about 18 to 20 minutes, until the scones are well browned and spring back when pressed gently with your finger. Serve right away or toast to reheat for best taste.