I am a watchmaker and goldsmith and in answer to your question it
depends on the shape and type of glass. If it is round and has a
dome the circumference of the glass will be compressed to inserted
the glass, if it is round and flat in will be glued or possibly an
interference fit ( glass is slightly larger than bezel it fits in
)and pressed in. If it is an irregular shape, generally anything
other than round, it will be glued in.
Taking these glued one out will be a problem because generally the
glue used sets rock hard and even if you break the glass to remove it
there is often further difficulty in removing the glass fragments and
glue which is left in the bezel and care needs to be taken not to
damage or distort the case whilst removing these. Using a solvent
may work as long as you know the glue used and the glass material
The compressed type will push out from the inside but you will be
unable to refit it without the correct tool.
I would respectfully suggest you take this to your nearest
watchmaker and have him take it out for you and replace with a new
one as required and include this in the repair price.
Regards Alan UK
The Watch & Jewellery Workshop