Hello, Iím a newbie & doing my best to do as much research & educating myself as I go. Honestly itís overwhelming. My first question is why do my clear glass marbles that are a reddish color have a design or pattern I can only see under black light? Any help is appreciated, thank you. I will probably be posting a lot of pics of marbles really soon, needing to know types & if any are of value. Again, thank you in advance