One who collects order decorations and medals needs to understand and be knowledgeable about the mechanics behind crafting those precious items we all seek.
One of the steps in crafting order decorations is the finishing of attributes like golden swords or oak leafs. Take the Prussian Red Eagle Order for example. One may wonder how it is possible to create a red and yellow gold effect on a monolithic piece? Yet, the answer is rather easy. Two facts before we go into detail:
a) every metal is an alloy
b) gold can contain higher amounts of copper, which gives it a reddish hue.
Swords as an attribute for war merit, were initially crafted in red gold. After the assembly their hilts got dipped in hydrobromic acid. The acid will dissolve the copper out of the gold and leave the pure gold behind which looks now yellow, just as pure gold will appear.
The parts not exposed to the acid remain in their red gold color. The parts to remain in their original red gold color were likely covered in an acid resistant coating.
Dissolving copper out of a gold alloy surface creates a pure, yet spongy gold surface appearing in a frosted look. This effect can be further used to create those beautiful surfaces, like on an oak leaf of the red eagle order or wherever the look of pure frosted gold is desired. Certainly most of those surfaces are shined up today due to cleaning and polishing; few remain:
As the reader can easily see for themselves. the targeted polishing of some of the leaf veins and cutting more details into the leaf bring the original red gold core back to the surface.
I be interested to see if anybody has similar decorations, German or not in his/her collection to share?