It seems that Steinschoenau is still nowadays the only place in the world that produces this specialty: Enamel Overlay fittings. 

The main parts of the fittings are made from three layers of glass that are fused together: opaque white on the outside, then transparent ruby, green or blue in the middle, and finally a base of pure Bohemian crystal. The top white layer is then hand-cut through to reveal the middle layer thus creating small ‘windows’ letting colored light come through them. The finishing touch is added by hand-painted floral patterns throughout the piece. The High Enamel light fittings are further distinguished by a gold undercoat hand-painted with floral decorative motivs in high relief.

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