How do I tell if vaseline glass is really vaseline glass?

Question

My dad collects all sorts of antiques, and my mom really likes old glassware, so we have a lot of depression-type and carnival glass in our china cabinets and secretary bookcase. I learned that shining a black light on a piece of vaseline glass will make it glow bright green (it's radioactive!). However, the glass itself is bright green, and black light makes anything neon colored glow!

Do I have to get a Geiger in on it, or is my technique all wrong?

No, no, uranium was added to the glass to make it green-yellow. Science class tells me that uranium is radioactive. It's not highly radioactive or anything, just above background levels, but it's still radioactive, which is both cool and creepy.

Answer 1

Black light does NOT make everythng neon colored glow, although most bright colors glow because the UV (black light) in sunlight and fluorescent lighting DO activate phorescent atoms in the material. In fact, the reason vaselene glass is bright green is exactly the same - UV in ordinary light brings it out. It is easy to find green and other colored glass that is quite dull in black light - look at green glass coke and 7-up bottles.
So black light is the test. A little bit of the vaseline glass IS radioactive more than others and some made more recently is done with other methods and reacts much less to pure UV.

Answer 2

It glows not because it's radioactive, but fluorescent. Black light is ultra-violet light, that's all, which causes some materials to fluoresce. So, no, you don't need a Geiger counter, just a "black light" or other UV source (tanning bed, etc.).