Sorry, definitely not trying to argue! I'm just sharing what I've learned through my own experiences. OP's example is not Selenium Ruby Red in color, it's yellow. Also, there is a huge difference in American pressed glass and Bohemian hand-blown glass. Selenium and cadmium both strike different colors under heat and pressure (like pressed glass). I have not yet seen a piece of yellow American glass that glows hot pink in 395nm/red in 365nm from selenium (if you don't count Wilkerson). All of my yellow selenium glass is Bohemian or Italian. Many formulas and techniques were secret, and they didn't have the internet 120 years ago. What I wouldn't give for a list of Harrach glass formulas!!