color changing glass.

alright, so here is the deal. i was examining one of my finer bowls today, a sherlock to be precise. And i dont smoke out of it too often for the bowl is large and shallow, so solo smoking isnt a common thing, but its good for company or a large group. Anyways, i was looking at the coloring which i was starting to get, and i remember in the past when i looked at it, it was rather faint, and now it is strong, which now brings me to my query. It has 2 completely different colors which the fuming creates. It has many different swirl patterns and colors, but the bowl has 2 different fumed colors. Now i know that when they fume the pipes that they use silver or gold, and i was under the presumption that silver creates a sorta blue hue, and gold created a yellow/orange hue on the glass. My pipe has both a yellow and blue colors on the inside. So i was wondering if anyone else had a 2 colored bowl such as mine, or even if it was possible or a more common thing than i actually think, though i have several pieces and none of them have 2 colors like that. Not to mention its not like the colors are swirled inside, it is more of a 50-50 deal with a clear line down the middle of the bowl.

you cant really see it as well from this angle, it just seems weird to me though. thanky in advanced for any good answers, and a congratulations to anyone who has scored a rather dazzling bowl themselves. It hits like a champ.