Yes it is there is a spacial blade thet can cut the marble but you may want to hire someone that speacilizes in that field

Ermm. . . Intresting question

But i do not know ?

Cultured marble does chip kind of easy if you cut it wrong, You can use either a wet or dry cut diamond saw, like for tile, to cut it.
Just run a piece of duct tape around the top where you want to cut.
This will give you an area you can draw you line on and help keep the
vibration of the blade from nicking the edge. Try to place the cut edge against a wall so any imperfections will disappear.
I have do this all the time for the same reason, I can buy a clean used top for under 50 bucks from habitat,and cut to fit.

Luck

You can rent a dry cut saw, looks like a miniature circular saw for under 50 bucks with a blade at most tool rentals.

Chris