[If anything, the stone will probably feel a bit cold no matter how much Vash holds it; Moon El is known for being very chilly. It might also make Vash a little sleepy, but that's just a side effect. Unrelated to the Illuminous Phenomenon, of course.]

Huh? Really? Well, I guess it is a holy artifact... Just don't lose it, okay? Ms. Shopkeeper made a face when I asked her to get it for me, and I don't want to ask her for another, haha.