When I insert a faith plate either from the prefabs or by creating the prop_dynamic myself it appears correctly in Hammer but when I compile it and load the map in Portal 2 the top surface of the faith plate is this strange white reflective surface instead of how it should look and how it appeared in hammer. the rest of the faith plate appears correctly.

There are no errors in the compile and I haven't found this problem with anything else so far. Any ideas?

You have no cubemaps inside of your map just select the entitiy tool and type in env_cubemap and place it about 64 units above your faith plate

Thanks! It works great now! All these fancy reflections and dynamic lighting and stuff were not around when I last mapped with Hammer.

Uh, was that before 2003? Because if so then welcome to the modern age. Specularity and cubemapping has been around for about that long.

Heh, don't make me feel that old! I think the last time I mapped was for HL1, well before Steam and back when the Hammer Editor was called something like Worldcraft. So cubemapping I'm good on and I have a healthy aversion to just dropping your map inside a big hollowed cube to avoid leaks. But we had none of these new-fangled textures that emit light or fancy reflections back in my day. I think we had less than a dozen entities and we really could only use 5 or 6.

I mapped in Worldcraft as well. It's amazing what changes in the span of like, you know, 14 years. There's no point or honor in clinging to a long ended era. Technology marches on.