Overlaid or so-called cased colored cut crystal
This technique is used to produce a two-tiered effect in the crystal. The inner and outer layers are of different colors, producing an appearance of depth in the piece. Sometimes, the outer crystal layer is ground away in patterns, leaving the inner layer to shine through. This technique produces stunning results.
Amber color has been popular for the last decade or so. It is very pretty, and gives crystal very contemporary and fresh look.