From: John De Armond
Subject: Re: "Woah" Uranium glass
Date: Tue, 22 Jun 1999 05:44:33 EDT
Newsgroups: rec.crafts.glass

Brian wrote:
> 
> Thorium is another radioactive element, it is formed when Uranium decays.  It is
> a beta and alpha emitter, and is not terribly active.  It is not something that
> the average person wants to have around, but it is not at all in the class of
> cobalt 60 or Strontium 90, which are powerful gamma emitters that release great
> quantities of dangerous radiation, rather than the milder alpha and beta
> emitters like thorium and U238.

Hate to be picky but...  Sr-90 is a pure beta emitter.  While Th is
in the decay chain of U, thorium of useable quantities are mined
from the earth.  Thorium is one of the heavy, mildly radioactive
transuranic elements, located in actinic row of the periodic table
along with uranium plutonium and several other interesting metals. 
It is refined from its phosphate ore called Monazite.  Other lesser
quality ores are of the oxide form and are called thorite and
thorianite.  More than you possibly could want to know about thorium
can be found at
http://www.shef.ac.uk/chemistry/web-elements/webelements/elements/text/key/Th.html

Relative to glass, I can't imagine what art application thoriated
glass could have.  Thoriated glass has very low dispersion and a
very high refractive index.  These qualities make it an excellent
optical glass and indeed, this is a major non-nuclear use.  Because
of its low dispersion (ability to "produce a rainbow"), anything
artistic made of thoriated glass would be dull looking and would not
sparkle.

Thorium is a nuclear fuel and can be transmuted into U-233 by
neutron bombardment.  U-233 is a poor but viable fissile material
(capable of being made into a bomb.)

Thorium has many common non-nuclear uses.  One use that almost
everyone is familiar with (even though most don't know it) is the
Welsbach mantle, otherwise known as the Coleman Lantern mantle. 
Thorium is what gives the mantle its characteristic greenish
brilliant white glow.  And yes, it will make a geiger counter
chatter away.  Other uses include thoriated tungsten filaments in
tubes such as the CRT on your computer and thoriated tungsten
welding electrodes.  Thorium oxide is an excellent refractory,
having one of the highest melting points of all substances and
having excellent thermal conductivity.  I've already mentioned
optical glass.

Not familiar with thorium enamel.  Would love to know.  Details?

John