The mantel is 1/2" raw steel, that was installed before the stone, so that it protrudes to look cantilevered.

thank yoi! did you wrap the steel or is stone placed underneath? It’s a little hard

to see those details in the photo. Thank you again!

If you continue looking through that project there is a good close up, side view of that mantel that may help your understanding.

No the stell is not wrapped, the mantel is solid 1/2" thick steel. As you can see the mantel is surrounded by stone on all sides.