This link is pretty interesting because they actually tried washing and hurting a bit samples of the various kinds of silk, and they describe what happens, what changes and whether or not it could be considered ruined depending on what the silk is used for.

(also, I'm deeply for CampWashSilkWithWater, btw, and also WhyBotherWithDryCleaningWhenYouCanAvoidIt)

How to wash silk

So there you were, browsing our silk fabric selection and dreaming up a fabulous new dress or pretty top, when all of the sudden your practical side burst in and said: But it’s silk… how will you ever wash it? Well, we’ve been wondering the same thin…

^Sartor