Crystals in a Rock?

I live in Utah. (no I'm not mormon) We have a rather long river that runs all over my town, my boyfriend and I were walking along it looking for river stones to paint. I looked down and in this large grey rock was aguamarine crystals growing out. We chipped away at the crystals and later dug out the entire rock, so far as we keep digging we find more crystals, some clear. It looks a lot like the Green Beryl, but we're not exactly sure, either way we found something really cool. W e also ended up finding clear Quartz. I'll keep you posted in case we ever find anything else.