Rock with play of color, what is it?

[davbret]

Found this at a local flea market and fell in love. Was told it was golden obsidian, but it doesn't look like any golden obsidian pictures I've seen. Weighs at least 20lbs, about the size of half a basket ball. Not sure what it is. Has definite "play of color" like an opal. I'd try to better describe, but it's really hard to define due to the colorations, stridations and "opalescence". I've included a photo that best shows it, but to truly see it you have to see the way the colors and sheens change with movement and light. I uploaded a quick vid to youtube to show this.

Thank you very much for helping me figure out what I got! ;D

youtu.be/rRgvXCJLvVI

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