Generally speaking, the market for Bohemian blown and cut overlay glass came from a strong demand from the European market.  Please note, all the images in this blog are of the same necklace.  It is a bi-colour Czech necklace probably dating to the early 1900’s with an interior of anna-grun with a blue overlay over that.  Hence it glows with uranium under black (UV) light.









Marketing of this two colour glass was aimed largely at a novelty market and the craze for this type of Bohemian Crystal began in the 1820’s.  Muranese and Bohemian craftsmen had long perfected the art of combining two colours of glass using traditional techniques, rather than blowing.










The early 1800’s drove the Bohemian bijouterie companies to strive to find a way to include this popular type of glass in their jewellery.









There are several ways to make this type of glass – firstly is by the addition of chemicals.  Another is to simply overlay a rod of an existing glass colour, with an outer coating of another clear colour glass.  Since both colours are transparent, it is difficult to determine where one ends and the other begins.










Advanced glass makers, like the artisans of Bohemia used another way to produce glass with two colours.  This method is called ‘striking’ and is achieved by reheating glass to a certain temperature, where its colour will change. When only a part of a piece of glass is reheated, then it produces two colours within once item.