classic!
You could try using some of the industrial strength double sided sticky pads...
ive got some thats on a small roll and its very very sticky and may have a good chance to get it out.
I think the marble may be too shiny for the super glue to bond but that may be worth a try.
Failing that get your vacuum cleaner... provided it has one of the long thin attachements you can fit to it that you would use for cleaning down the side of car seats etc >>
fit that on, then get a straw, and some masking tape, and fasten the straw to the end of the nozzle using the masking tape as a seal...to create a micro nozzle with very high suction.
This may well get a good grip on the marble
In all seriousness I have used this technique on several occasions, the last time to retrieve a ball bearing from inside an engine bore when a spark plug was removed (long story!)
It worked a treat but you can only really leave the vacuum on for 5 or 10 second bursts or it will overheat the motor as its trying to suck a lot of air in through that straw!
good luck and may the force be with you