Boron is the
chemical element with the symbol B and has an atomic number
of 5 and an atomic weight of 10.811. 
Things you might
not know about Boron:
1. Boron
compounds are used to produce borosilicate glass such as Pyrex.
2. Amorphous
boron provides a green color in pyrotechnic devices.
3. Boron-10 is
used as a control for nuclear reactors, to detect neutrons, and as
a shield for nuclear radiation.
4. Silly putty
contains about 4% boric acid, which is critically important for its
bounce characteristic
See GC2XAY2 - Hydrogen, for an explanation
about this series of caches.