The third character have to be considered is a silk duvet cover. A silk filled comforter should always be encased in a removable duvet cover that can be laundered regularly. The covers are available in a vast array of materials from different weaves and grades of silk to ones made of organic cotton to a combination of materials. There are various kinds of duvet covers you could choose. Which to choose is up to you, but I recommend a silk cover for the silk comforter. Why skimp on the cover? But if the silk comforter you are buying is for a child, opt for a cotton cover because it is going to stand up to the wear and tear a child will subject it too better than a silk duvet cover will.
You could choose either according to your joy and love, but do remember, comfort is first!