Do some light studying on quilt history and you will find that mixing fabrics has been accepted for years and years. Some of the most beautiful quilts were from the late 1800's and early 1900's -- all of those crazy quilts that incorporated silks, satins and velvets, along with the lacy embroidery stitches used to hold the blocks together. Many of them did not last "forever," but they were certainly beautiful to look at.