What is "musset"?

I came across the word "musset" in Gregory Maguire's Wicked--

Her green traveling gown with its inset panels of ochre musset suggested wealth, while the black shawl draping just so about the shoulders was a nod to her academic inclinations. (p. 84 in my edition)

Does anyone know what exactly the word refers to? It plainly has something to do with clothing, but what in particular? Is it just an invented word? It's not in the OED, and my Google searches led to naught, but I'm wondering if it might be a recondite technical term for something.

The word musset was invented by the author (Gregory Maguire).

Having replicated the OP's lack of success in finding any online definition of the word, I acted on a whim and sent an email to ask him. He very kindly replied a few hours later with:

Ah, you have found one of my invented words, employed to make the world of Oz that little bit more unfamiliar than we expect.

I imagine it to be somewhat velvety, but what do I know?

Sorry to have given you an exercise that ended in — author trickery!

Cheers,

Gregory Maguire