How to hang very heavy (marble, granite, quartz, etc.) shelves on drywall and studs?
Anchoring them to studs is just fine, your main problem is going to be getting brackets that will support that amount of weight. The amount of weight each bracket will support will be printed on the package. I would consult your granite or stone supplier for weights of their products. 

You MUST make sure that you're anchored into studs, though, and preferably with three inch wood screws that are NOT drywall screws.