Heard that there are 3 different grade of marble - depending on the clarity of the marble.
Grade A, B and C. Grade A is the most expensive. What is major difference among them? Nowadays most of the marble table are coated? How can I differentiate them from natural marble when I walk in to showroom to check?

Roughly how much would it cost for a marble dining table set with 6 chairs? Let say the rectangle table size is 5ft x 3 ft.

The reason im looking for marble table is it does not shake and very solid compared to ceramic table and wooden table.