I don't normally buy irradiated insulators, but when I saw a sapphire blue NEGMCO beehive listed by swordplayer on eBay I had to purchase it to compare it to my real one. In my research on NEGMCO beehives I tried to create a sapphire blue to see if the real ones could be replicated. I took an aqua one and it came back purple after heat treating. I took a green one and it came back inky cobalt blue. Eric has managed to produce what at first glance is a very close proximity to the real thing.
My real sapphire blue beehive is on the left and the altered piece is on the right. Notice that the altered piece is actually a light purple/sapphire blue two-tone. It is not marked as being altered (yet). The dome of this altered piece is very close to the real thing; quite scary actually. Any observed purple tint to the real one is due to reflection from the altered piece beside it. I suspect Eric may have used a lower radiation source or didn't expose it for as long to get this effect. My guess is that a strong dose of radiation would have turned this one purple like my other altered one.
I plan on doing a display of NEGMCO beehives at the Farmington National that will include my irradiated specimens. In the meantime, all you collectors of NEGMCO pieces (I'm speaking directly to you, Dante) be very careful of so-called sapphire blue pieces. Unless you have a real example to compare to, it may be near impossible to tell the difference!