I cannot recollect what figure of speech is "silken colour".
Part of speech? Maybe that is what the OP meant.
Isn't the analogy with wood/ wooden the one that applies here? That is, silken might also be made of silk.
I think he's talking about synaesthesia too, unless he means in a physical sense that the colour of a fabric is literally shimmering.
Assuming the OP is not a female. Sounds like a male style.
Okay, let's go with "he or she". ;)