Can't tell, looks like their in a glass case, can't see if there's pontils or not ?? It does appear to be mica, maybe if you could get an in hand shot or two ??
Glowing is much different than a UV. reaction. A UV. reaction only occurs as the uv. light is applied. Glowing means the artifact continues to "glow" after the light source is removed.
Not polished IMO I can see a dimple in pic #6 with smooth edges, I highly doubt as akrooka does that there's any vitro around that's been polished, their quality control was outstanding, nice mib BTW
Gibson hardly ever marked anything he made I heard, allot of copycats out there, especially the snakeskin, the OP skin does look like his work though IMO