Line a rimmed cookie sheet with parchment paper, set aside.
In a medium mixing bowl, whisk together dry ingredients. Using a fork, cut in coconut oil or butter, until it resembles coarse crumbs. Gently fold in blueberries. Make a well in the center of the flour and add buttermilk. Fold together with flour and blueberries, just until combined or until dough leaves the sides of the bowl.
Turn dough out onto a working surface, lightly dusted with flour. Use hands to shape dough into 1-inch thickness. Use a biscuit cutter, dip in flour, and cut dough into 10 biscuit shapes or cut with a knife into rectangle shapes, place on the parchment-lined cookie sheet or (nonstick cookie sheet). Brush scones with buttermilk. Bake until golden, about 15-17 minutes. Allow to cool 5 minutes before adding the glaze.
While scones are baking: Combine cornstarch and salt in a medium saucepan. Slowly stir in lemon juice and honey, stir until smooth. Add lemon zest and cook over medium heat until thick and glossy. Cool slightly and drizzle over warm scones. Enjoy warm!