I found this while at field camp for my baccalaureate in geology in the Bighorn Basin in Northwestern Wyoming. If I recall correctly, I found it on a shelf system from the old rivers that cut the Bighorn Basin back down, east of the river that runs the eastern side of the Bighorn Basin. I am certain it is sediment for farther north, possibly as far as southern Montana. It has a nearly-adamantine to adamantine sheen, very glassy, and although the bulk is a blue-green color, there are intrusions of a much deeper and greener green scattered throughout the stone's interior. Light passes through it completely such that I can see through it when backlit only, and barely at that. It would not scratch against quartz, but the quartz seems to kind of grind against it. I think it may be a form of Beryl, but I want to have an additional opinion. Thank you for your help
