Add it Up in Slate Blue Designer: Alexia Abegg Collection: Add it Up Substrate: Ruby Star Cotton - great for garments and quilts Made by Moda fabrics What is Ruby Star Cotton? Ruby Star Cotton is 100% premium quilting cotton that is slightly lighter weight than most quilting cottons on the market, making it more versatile for both quilters and garment sewers alike. It has a smooth, silky finish and a soft hand. All our Ruby Star Cottons are screen printed in Japan.