The big one came
Mine have definitely been flattened and prepared for razors. I'm glad to because these things are hard. They feel harder and finer than any of my Arkansas stones. I bought them from different eBay sellers and neither one of them has anything available at the moment.
That little green one came from
https://www.ebay.com/usr/custommadesharpenersandkinves
The larger beige/gray (I'm real colorblind and it changes quite a bit depending on light) one came from
https://www.ebay.com/usr/sajohnso-960
I have finished about 10 razors on the green one. The feeling is keener than an Ark. WAAAYYY keener than coticule. Not as smooth as a coticule, but pretty close to smoothness of Arkansas. Dangerously sharp. I split my cheek open with a Japanese wedge just by going a little too quickly against the grain. Still have a tiny scar from a couple of months ago.
I have only finished 2 razors on the beige/grey one. I haven't scared myself yet, but I also have only tried 2 kind of problem child razors so far. Haven't thrown anything real scary at it, but I have every reason to believe that it is just as capable as the little one. They look a lot different but they feel the same.
Jasper and novaculite are both made of microcrystalline quartz so it makes sense that they would have similar properties. Jasper isn't really a geological name like novaculite though so each piece is going to have a lot more variance than with Arkansas stones and my experience is only with these two pieces of jasper and about 6 pieces of hard Arkansas.