An old chemistry demo: mercury with blue crystals in ampule

[mododavid]

I am an PhD student (emphasis in inorganic). I am currently working with a local high school chemistry teacher to put together lessons and go through all the stuff left behind by the very old chemistry teacher who retired. We found a large, sealed test tube (ampule) with mercury and some blue crystals in it (the crystals resemble pieces of cobalt glass). I've seen this before, but it was red crystals last time (I don't think they were cinnabar, but maybe.) I think it's used to demonstrate some chemical or physical properties. Beyond that, I'm clueless. Also, the old chemistry teacher, who was there for over 30 years, said that the tube was purchased by some teacher before she taught there. So, it's a very old demo, and I can't find it in any science teacher supply catalogs. Anybody have any idea? I have a pic, but I don't know how to post it here. Thanks for any help.

[Magnesium24]

mododavid - I found one in my lab, just as you described. Have you figured out what it is yet?

[jimsfriend]

I found this http://pubs.acs.org/doi/abs/10.1021/om00097a004
It mentions mercury and cobalt and red crystals. All things that are in the OP. Other than that I don't know anything about this. It could just be a demonstration of large mercury compound, but that sounds like a pretty boring demo :p

[ikrase]

Are you sure that it was mercury? What you describe sounds vaguely like N204 tubes that were in my high school chem lab.

[Magnesium24]

This one seems to be mercury. I found two N2O4 tubes as well.

[Magnesium24]

Finally took a picture of the ampule. Still no idea what it is. No response to heat (65 degrees C) or blacklight (395 nm).

http://www.flickr.com/photos/64213337@N07/7350206338/in/photostream

[PM 2Ring]

Those blue "crystals" look suspiciously like Blue Indicating Silica Gel. I don't know what they're doing in a sealed ampule containing mercury, though I guess they'd prevent hydroxide formation, keeping the mercury surface nice and shiny.