hhhmm interesting, thanks I don't know if the last one will work seeing as they have metal clasps glued on but i'll definately try the first and third one. Will any alcohol work?
I was wondering what you meant. hhmmm, tapping a key on it sounds like a quiter version of tapping the window but completely different to my watch although is that likely to be plastic?
All opaque jewelly has a refractive index which separates one stone from another and is used to check real diamonds from fakes but also can be used for other gems.
The easiest way to tell amber is to rub it fairly vigourously against a cloth (any sort but a clean duster would be ideal) and then hold it over some small bits of paper. Real amber picks up a healthy static charge and will cause the paper to be attracted to it. Or so my mother told me......!