Hmmm...not much you could do with that cut to hide any flaws! They are interesting, but not sure if I 'like' them or not. Kind of looks like a piece of glass...but that opinion could change if I ever see one in person, in different lighting, etc. That first ring is pretty though!
Gonna throw some table cut diamonds into the mix...
"In 1912, workmen discovered a box of jewelry hidden under the floorboards of a house in Cheapside. The jewelry has been dated to between 1600-1650, and it was the work of a jeweler who supplied jewelry to wealthy merchants and their wives. This discovery, which included about 230 pieces of jewelry, is known as the Cheapside Hoard..."