No fabric content listed, feels like a cotton or cotton/blend (could be wrong). The collar is backed with organza. The skirt has a tulle net lining for extra fullness.
Center back nylon zipper closure with hook and fabric eye at nape.
There are a few faint tiny stains throughout (see photos 10-12), no rips or tears. No fabric content listed. Main feels like cotton or a cotton blend.

Tag size of girls 6, actual measurements
chest: 28"
natural waist: 25"
length: 25"

This item is sold from an excellent, highly rated vintage boutique in El Cajon, CA.