Beautiful Rock identification help
It appears to be a piece of malachite, a copper carbonate mineral. https://en.wikipedia.org/wiki/Malachite The bright blue is probably azurite, a copper carbonate mineral, usually paired with malachite. https://en.wikipedia.org/wiki/Azurite
You didn't mention where you found this lovely specimen. From looking at the geology map for Grayson county, most of the rocks are sedimentary. https://txpub.usgs.gov/txgeology/
It's a gorgeous specimen. Thank you for sharing!!!