When a mirror this size stands on a console top, the load stops being spread and becomes a point. The mirror's base rail is narrow, its frame is heavy, and all of that weight lands on two short bearing areas on a slab of stone. Marble is strong in compression but unhappy about concentrated loads on an unsupported span.
So our master Indian artisans build the mirror's footing into the table rather than resting it on the stone. A shaped timber plinth is fitted along the back of the top, sitting directly over the rear rail of the console frame, and the mirror stands on that plinth. The load travels straight down through timber into the frame and out through the back legs, and the marble carries only what is placed on it by hand.
The plinth is finished to match, so it reads as part of the design rather than a bracket. Its height is chosen so that the mirror's bottom edge clears anything you are likely to set on the top - a lamp base, a bowl, a tray - instead of trapping it behind glass.