It is important to remember that UV adhesive is cured by a long wave ultraviolet lamp when the UV light penetrates the glass (or crystal), and it then activates the curing cycle.
When bonding color bases to clear or jade uprights, as long as the UV light can penetrate the clear or jade upright into the joint surface, it will cure. The challenge comes when both the base and the upright are colored. When the colors are not too dense, the UV light can still penetrate and cure the adhesive, but it will require a much longer exposure time.
For more dense colors (like black), a regular-powered UV lamp is rarely sufficient. For this task, our production facility uses a high-powered micro discharge UV lamp (the Spectroline SLX3500C). This UV lamp has the power to penetrate almost any color of glass or crystal. Another option is to use a two-part adhesive that is activated chemically when the adhesive comes into contact with an activator agent. This adhesive does not require a UV curing lamp.