After a bit of digging, it appears to be a set piece being designed by the Tamriel Rebuilt folks for their Hammerfell project. It does have a slight connection in that they managed to dig up a quote by the most official of ex-officials on TES lore. In terms of canonocity (real word, I promise you), I'd put it at tier 2.5. Between the extended lore and really good, really devoted fan's lore. Here's a linky (http://tamriel-rebuilt.org/forum/viewtopic.php?p=202148%F0%B1%96%A4). Look for MK, but not his post.
As for whether my personal gauge of canonocity is an accurate measure of everyone's personal tastes and whether or not people will still build theories based off of tier 2.5 or lower material, runs to their tastes. Personally, I would not unless it provides just a tiny little detail that was missing, but that's just me.
Now then, onto the more pressing matter: how would such an armor ablate a cut or impact and would such an armor also be decently flexible enough to swing a sword in? Remember, we're dealing with a fantasy setting here, so don't just say "It's made of rock powder that's been fused together by fire, it's brittle and will shatter on an impact, it's not viable."