Linen may have irregularities because it is a textile made from the fibres of the flax plant. This is in no way considered to be a fault.
Genuine leather may have small markings. These characteristics are completely natural and normal, and should be expected in leather.
Silk has tiny imperfections because it is a natural product.
Many of our wool products are hand loomed and as such have irregularities that reflect their handmade nature.