Hi there,

I know there's a cielo blue that was used to paint doors in Yoruba (west african)culture to keep out evil spirits, and it wouldn't suprise me at all if that transmuted through appalachian culture. here's the color:

http://3.bp.blogspot.com/_E66IzYq9uJQ/TLMwAfk7C1I/AAAAAAAAEiQ/KCC0-Qegb_E/s1600/Cuba.BlueDoorMask.9.5.10Web.JPG