Have you seen a fabric that seems much like linen, but you’re pretty sure it isn’t? If you are interested in vintage clothing you will see this fabric regularly. From the VFG Fabric Resource:
Butcher cloth 
Butcher cloth is rayon or rayon/cotton, spun and woven to resemble linen with linen-like slubs. Butcher cloth used to be called butcher linen, but that is no longer correct according to the U.S. Federal Trade Commission. 
Uses: Dresses, suits, skirts 
See also:
 Butcher linen, Linen

Machine-embroidered butcher cloth
©Vintage Fashion Guild - Text by Margaret Wilds/denisebrain,  photo by Hoyt Carter 

Robin's egg blue butcher linen dress currently in my Etsy shop