It stays standing because the concrete is reenforced by a skeleton of PURE BLU CRYSTAL. If you were to chip away at the cladding, you might catch a glimpse.
Coming out of the Varsity cinemas last night onto Balmuto street the crystals in the precast had a really interesting glow to them, presumably by light picked up from the street lights. It's a very impressive effect.
Click on the thumbnail to enlarge, then click again on the image for full size.