Very nice specimen of botryoidal chalcedony, also known as grape agate.
Grape agate is a gorgeous, naturally occurring mineral that, as the common name implies, resembles grape clusters.
Grape agate is typically priced by size and quality with very large, nice quality specimens getting up into thousands of dollars.
This particular specimen has very prominent grape clusters with vibrant purple coloring!
Makes a gorgeous home décor or conversation starter piece!