The saia, or skirt, is a simple but striking component of the traditional costume from the Minho region of Portugal. This is part of the Traje de Lavradeira, or working woman's costume. It is meant to hit the mid calf, but some dancing groups shorten the saia for ease of dancing.
The main fabric is a handmade red wool, with white and black stripes. The bottom facing is made of a black wool (I'm not sure, but I think it's worsted--feels like felt but is very soft). The black facing is pinked along the upper edge, and is decorated with a continuous embroidered image of flowers, vines, and berries which mimics the embroideries of the 18th century.
The interior facing on this particular model is made of a nautical themed cotton. The saia is entirely machine stitched, except for the embroidery. This saia actually wasn't bought in Viana do Castelo; the saia, bodice, and apron were bought in Aveiro by my grandmother. I believe the sewist who made this was attempting to imitate the styles of Viana do Castelo, as this piece isn't representative of the traditional costume of Aveiro. This may account for a few differences in decoration and design (though minimal) from the original costumes.
The saia is cut as one large rectangle joined by one side seam. It has an ivory cotton waistband facing. A strip of elastic is zig-zagged in place along the middle of the waistband and facing. Traditionally, these skirts are deeply cartridge pleated along the waist, and are sewn to a cotton tape of a matching color which is used to tie the saia and secure it to the body. As this saia was made for a child, it's sensible that the waistband was elastic: I wore this from the time I was 8 to about 14!
Again, for more information and pictures of the variety of this costume, I recommend Folk Costume & Embroidery's informative post.