More radioactive junk at my house

The previous post about radioactive junk is here:

I've wanted to own a glow-in-the-dark watch for several decades now.  They make Tritium watches that are pretty inexpensive, but the half-life of Tritium is pretty short, at 12.3 years.  What that means is that in just 12.3 years, the glow will be at half the intensity as when the Tritium was new. 

I'm old school, so I was interested in a Radium watch painted with Undark.  Radium has a half-life of 1600 years, so it shouldn't noticeably dim for decades!  I saw a Radium watch at an online auction that was pretty cheap, so I bid on it, and won the auction.  I think it cost $30,and that included shipping.

Unfortunately, the one thing that this watch does not do is glow in the dark.  I did a bit of research on that and learned a couple of things.  Radium watch dials are painted with a blend of Zinc Sulfide and Radium.  The Radium emits alpha particles, and that radioactivity will last several lifetimes.  The alpha particles interact with the Zinc Sulfide, and it is this compound, when struck by the alpha particles that emits a soft bluish light.

Below:  A vintage Radium watch.  This glow does not depend on recharging it under a light source.

 As I have stated elsewhere though, being in close proximity to alpha radiation does a great deal of damage.  Take a look at what the alpha particles have done to this watch crystal over the years.  This is why Radon gas is such bad news to breathe.

Because the Zinc Sulfide light-emitter is in contact with the Radium, eventually the Radium destroys the Zinc Sulfide.  This is why the dial on my old watch doesn't glow much at all. The Radium is there, and it's still radioactive.  I verified that with the Geiger counter.

The detector is in alarm in this photo.  Background is about 25 counts per minute.

It's apparent that the Radium has indeed damaged the Zinc Sulfide to the point where it cannot glow any longer.  Fortunately, I've found a place that retails the luminous (non-radioactive) part of the paint.  I just need to place an order, and then find some time to overcoat the old paint.  Also the crystal is a bit scratched up, so I'll probably replace that and polish the case up at that time.