The material I used is platinum clad niobium. All the colors are anodized while the black is a niobium oxide. All the white parts is the platinum, lightly brushed.
Yes, the engraving for the black parts is done first then blackened by heat treatment. next the colored parts are engraved and anodized in the order of colors starting with the highest voltage. The platinum provides the "white" parts. The .010 thick piece is the captured in a Argentium silver "bezel" and inserted in the .052 Argentium body and soft soldered (excessive heat is to be avoided).