What's this fabric? Sewing Machines Parts and Sales in Los Angeles

I'm wondering what kind of fabric these jackets could be made of. I absolutely love the texture and the way light hits it, most easily visible on the one on the left. I had initially been thinking either denim or canvas but neither one seems right. Could it maybe be a heavier linen? I've never really looked closely at any linens before but I just saw some on Etsy and the texture looks strikingly similar (nearly identical). Any help is appreciated.