Willow Creek Jasper is one of the finest and most coveted of the porcelain jaspers. It is mined in Idaho on private land. Unlike most of the mudstone, it is formed in nodules rather than layers. When sliced it produces concentric bands that create a delicate mesh of scales across a spectrum of pastel colors.
This is another one of those stones that I would love to cut more of, but cannot afford. My budget threshold is still under $10/pound and I won't even entertain anything sold by the carat or gram as this stuff is. However, I was able to find a couple small pieces on the clearance tables.
Here's an article all about the stuff. Also, do a search on Etsy for Willow Creek cabs to get a good idea of what's possible.