system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why does water stain silk?
gpt
Two reasons:

* Many dyes that are used on silk are water soluble, which means that the dyes can run if you get water on it.
* Silk fibers become more delicate when wet, and, especially if you're rubbing the fabric, can slightly damage the fibers in a way that causes the fabric to look stained.