Here is some information that may help you. Here is a link that might be useful: Marble

Same thing happened to my cultured marble shower pan. A loud pop and then thin cracks extending from both sides of the drain hole. The original installer told me the same thing. He'd never seen this happen before and that I'd need to replace the whole shower because the wall panels sit on the pan top edges. When I examine the drain from underneath (from the crawl space under the house), I see that a 2x10 joist runs very close to the drain hole, close enough that the 3" plastic drain pipe is off vertical by 10-15 degrees. The pipe was obviously forced into position before the compression ring was secured. My theory is that this arrangement put great pressure on the floor pan, with the pan floor on one side of the drain hole being forced upward and the pan floor on the other side of the drain hole being forced downward. After 17 years of pressure, the floor finally gave way. My conclusion is that this was a serious plumbing error and I'm in the process of making my case with the plumbing outfit that did the work. They should have cut out a section of the 2x10 joist, thus allowing the drain pipe to be installed vertically, and then installing headers against the two cut ends of the joist. Seems to me the plumber is liable for the damage and the replacement of the entire shower.

You first need to determine (if it hasn't already) if your particular granite needs to be sealed. For daily cleaning (not polishing) I use a mixture of 50/50 alcohol/water and a microfiber cloth. I discovered the "home brew" over on the kitchen forum 6 years ago. So many of the products aren't meant for granite or the sealer. Stay away from acidic or non ph balanced products. Stay away from soap and water...it's too hard to rinse and after awhile you'll wind up with a hazy film on your beautiful countertop. 50/50 probably isn't necessary. Some people use less alcohol. Monica

Thanks Annz, unless they do a real nasty job of it I am pretty sure I would be happy with a repair. You have to get in just the right lighting to notice the crack at all but I do not want it to widen. My concern though is whether or not a crack repair is a permanent solution. I would not want to forfeit the chance early in the game of having it replaced. They are coming today to have a look. When I called the gal said wow we have Never had that happen. I find it hard to believe it never ever happened with a marble top install because I do know it can happen. I did not do my normal research and job overseeing because I have used this company before for countertop fabrication and they went well beyond fabulous. However, it was all different employees this time around.