It's certainly pearlescent, but not because it's from an oyster shell, despite the name we have given it.
That agate can create so many - and so varied - versions, all from the same mineral under huge temperatures because Agate is a silica-based mineral formed in voids in volcanic rocks millions of years ago.
It's one of our all time favourite scarves, and absolutely has to be seen in silk - and being worn - to be truly appreciated.