You're right Lydia, it means different things to different people at different times.

When I started collecting 'natural' meant untreated in any way. It still does most of the time (depending on the age of the dealer!), but now some people are adopting it for stones that have not been lab-created. I still use it the old way – a natural stone is untreated and unheated.

I've personally not come across any filled Ruby cabs, but I have to admit I've not been looking for them – I'm sure they exist somewhere. However, what I said regarding cut stones will still apply. Glass will always be weaker than almost any gemstone, it just depends how much is used.