Hm,  Nancy,  somebody on the KJV translator crew knew the color of 
the material was a golden brown -- his guess seems to be raw silk.

Ah, but the question would be "Was raw silk known in the western Mediterranean at this time?" The Romans were importing silk by the time of the Vulgate, I believe, if not soon after, but it would have been in a finished state, i.e. woven or spun thread. There are whole tomes writen about this, and it sure doesn't help that byssus was often referred to as "sea silk". From what I've read and studied all these years, I would say that yes, it IS byssus being referred to, not raw silk. Not a bad suggestion, however. One to ponder upon.