Better tell the BBC. There was a programme last week by a geologist
saying how geology and the industrial revolution had influenced the
colours available to painters and describing the rocks/chemicals used to produce them.
The programme name escapes me.

However, one shot showed the presenter using his bare hands to play with mercury
- swishing it around to see it ripple, break up into 'blobs' and reform again
(just as if it was a bowl of water).

Don't bother warning the presenter - he's probably dead by now from
either the fumes or from the stuff seeing through his pores!

Roger