This paper presents the result of an experimental study on the production of selenium ruby glass, particularly on the retention of the colorants during the melting and fining operations. Selenium, Cadmium, and Sulphur are necessary in the final glass to get a ruby colour. Moderate reducing conditions are conducive to the retention of a large percentage of the selenium in the glass, but when conditions are highly reducing, cadmium is eliminated almost completely. Too little attention has been given in the past to the chemistry of the entire glass batch and as a result operators and research workers have often failed to get a ruby glass not because the loss of selenium was too high but because they eliminated the cadmium by maintaining too strong reducing conditions. A balance must be maintained so that the batch and the atmosphere above it are sufficiently reducing to hold enough selenium in the melt but not so strongly reducing as to eliminate the cadmium. The use of Silicon as a reducing agent is suggested. Most of the work reported in this paper was done on Soda-lime Silica glasses. A glass of this composition, containing 1% of selenium, 0.6% of cadmium and 0.1% of sulphur will produce a ruby colour. It has been found that if the cadmium is added as cadmium sulphide the final glass will have sufficient sulphur for colour development. An arrested cooling procedure for developing colour is described briefly.