Either all or part of the wheel surface will have a very bright shiny finish almost like a chrome or polished look. If you look carefully you will see very fine grooves on the surface of the wheel these are machine lines created by the lathe diamond cutting tool. The wheels will also be bi- coloured i.e the sides of the spokes and insets could be black,grey,silver or indeed any colour.
Not all wheels can be diamond cut this will depend on the profile of the wheel face.
Your diamond wheels technician can advise you if its possible or not.