Those who plan on going to OMSI, can you look at something for me?

Yes I know this is a long shot, an a bit odd. But there was something I remember seeing in the science lab downstairs across from the big train engine. It was locked up in a cabinet thats about eye level. Lol i think the cabinet was black, but could very well be wrong. It was some element that was a little block that was see through but had a little hue of frosty blue to it. I dont remember what it was called but its one of the coolest things to me lol. I also remember reading it was very light too(weight wise)?