Sulfur is the chemical element with
atomic number 16, and is represented by the symbol S. It has
an atomic weight of 32.065. 
Things you might not know about
Sulfur:
- Jupiter's moon Io owes its colors to various
forms of sulfur.
- Sulfur is referenced in the Bible as
brimstone.
- Elemental sulfur was once extracted from salt
domes where it sometimes occurs in nearly pure form, but this
method has been obsolete since the late 20th century.
- When burned, sulfur melts to a blood-red
liquid and emits a blue flame which is best observed in the
dark.
See GC2XAY2 - Hydrogen, for an explanation
about this series of caches.