A small mosquito in a large drop of solidified amber tree resin. Sounds kind of nasty, right? If you ask people, some would say it actually makes a pretty nice piece of jewellery. Amber has been used to decorate the human body since prehistoric times. But it hasn’t always been called amber. According to the Roman politician Tacitus, this gorgeous stone was once called 'glesum' in the Baltic States. Glesum was considered to be very valuable in many parts of the world. The Greek word for the resin is "electron" (ηλεκτρον). Funnily enough, this is where the word electricity comes from! Why? If you rub a piece of glesum against animal fur, it becomes static.