Ocean;

As one of the other FT members pointed out on another of your threads, the gold, titanium, and "stealth" black finish is just that. A colour finish applied to the aluminum surface.

I first saw the gold finish Topas in Frankfurt in 1996, followed a decade later by the Titanium, and now by the stealthy black model. These special cases appear to be introduced periodically through the years. I understand that there are also special versions exclusive to the Asian markets.

The finish is very common to metalwork manufacturing, but has to be applied very carefully. I have some ball-bearing drawer slides from Germany that have a brass finish applied as part of the plating dip, final process. They look as good as they did when I bought the items many years ago, but the unique finish diminished the price, which is why I bought them. Please note that this is not the same as Iridite or a military finish coating.

I do not recall ever seeing a gold case with a red interior, which must certainly be as unique as the market group it was intended for. Somewhat akin to Swarovski crystals beaded onto Römer wine glasses.