Bungalow by Joel Dewberry for Freespirit Zigtone - Grassland 58 width Rayon Challis Rayon can imitate many other materials such as cotton, linen, silk and wool. The term Challis refers to the soft characteristic of the material. Rayon Challis is similar to voile but has a more substantial weight. Rayon typically has a sheen to it, but this particular weave, does not. It has an incredibly soft, touchable, non-slick surface similar to silk. Perfect for blouses, skirts or dresses.