This bowl was a bit of a surprise. The interior is suposed to be chartreuse! Luckly the steel blue color is beautiful!
Black Mountain Clay with 3 coats of white Amaco Velvet Undeglaze, followed by 3 coats of chartreuse Amaco Velvet Underglaze before bisque firing. Then 3 coats of Amaco's zinc free clear fired to ^10. I also antiqued the outside with a cobalt oxide wash (which turns blue-black on the black mountain clay) to accent the texture.
The texture was carved into thick walls on the wheel while the clay was leather hard.