Spot the frippet: saffron.

Saffron is one of the most expensive substances on earth. This is a very good thing.

Why?

Well, because, worryingly, it's poisonous.

You'd have to eat a lot of it to notice, though, unless you try gathering your saffron from the autumn crocus Colchium autumnale (true saffron comes from Crocus sativus). There's just an outside chance that eating Colchium autumnale will kill you.

Still, where can you spot it? Growing, hardly anywhere. You can't find Crocus sativus in the wild (saffron is the bright orange thread-like things that grow from the middle of the flower). Crocus sativus doesn't set seed, either, so if you come upon it by accident it's almost certainly something else. Each plant produces up to ten cormlets (lovely word!) a year which have to be planted by hand.

To get a kilogram of saffron you need over a 100,000 plants, which accounts for the price.

So where can you see saffron? The robes of many Buddhist monks are saffron in colour, though they're actually sensibly dyed with turmeric, which is very much cheaper.

The easiest way to see saffron is probably to look out for a dish of risotto Milanese, or bouillabaise, paella or biryani. Saffron has been used in fabrics, medicines and even in Alexander the Great's bath - but that's not really much help to us, though the Indian flag has a deep saffron background.

If you're in Sri Lanka then you need to ask for some kungguma poo, which is not only charmingly named but is believed to cure headaches.

Spot the frippet: saffron. This word comes to us via the Old French safran and Latin safranum from either the Arabic aṣfar, yellow, or the Persian zarparān, which means having golden stigmas.