Is the "marble" in Donnie's Lincoln bathroom makeover actually marble?

[fargone]

11. The facing walls are not precise mirror images

The facing walls at the head and foot of the tub have very similar but not mirror images. The top half shows greater similarity than the bottom half. I know nothing about the process of cutting and polishing stone. However the process has to remove some material from the cut itself and possibly more in the polishing. That could leave the facing edges with close to mirror images. The outside walls to the left and right of the tub are not at all mirror images. However the corners are nicely "book-matched". My guess is they used marble veneer which is usually 1-3 mm thick.