Word To Use Today - cobalt.

Cobalt can be beautiful, but it can also be very dangerous.

The German miners of the 17th century certainly didn't like it much. This was partly because it was jolly difficult to get anything valuable out of the rock in which cobalt is found; partly because cobalt has a habit of spoiling nice clean silver ore; and partly because when you smelted it you were likely to get poisoned by arsenic fumes.

This is why those German miners called the stuff kobolt, which means goblin. (No one ever seems to have a good word to say about goblins.)

If that's not enough bad things about cobalt, there's also the Cobalt Blue Tarantula, a particularly poisonous and irritable hole-dwelling spider from Thailand.

And, of course, there's also the cobalt nuclear bomb. Not pleasant.

But it's not all bad news: there's the Cobalt Blue Mbuna, a perfectly harmless little fish from Malawi; all that stunning blue and white Chinese pottery; blue glass; the Romanian flag; and vitamin B12, without which we would all be anemic, tired, forgetful and depressed.

And cobalt blue is a simply glorious colour.

Word To Use Today: cobalt. This word comes from the German word kobolt, which means goblin, because of the belief that malicious goblins (is there any other kind?) put it in silver ore.