[someone123]

I could be wrong but I believe the NRC addition at built at Dal a few years ago used real sandstone for a portion of the facade.

I don't think it's reasonable to expect large buildings clad in sandstone, but for a case like this where there's a small facade that's part of a much larger development it is more realistic. Granite is another really nice accent material. I wouldn't expect a highrise clad in granite, but it can be used on the ground level of commercial buildings. Some modern office buildings like 1801 Hollis and the Royal Bank tower have stone cladding around the ground floor.