How do I make a Chelsea Filter?

How do I make a Chelsea Filter?  It is supposed to help in identifying certain red, blue and green stones. Used to determine if a stone is natural or synthetic. Can also be used for detecting synthetic blue spinel and detecting dyes in certain gems.  

Without some incredibly expensive technology, you can't - the filters are made inside vacuum chambers, by applying almost vanishingly thin layers of special chemicals.

So like Kiteman says, buy it !

Kiteman5 years ago
I've not been able to find out how they are made, but they are available for sale many places online for under $20.