A very clean example of smithsonite after calcite, from Santa Eualia. These usually have a lot of broken crystals, but this one is remarkable clean--especially considering the size-- with only the expected bits around the edges.  This is an older piece, not from the greenish-colored find made a few years ago.  From the bottom, you can see crude galena and fluorite crystals frozen in the matrix, making it somewhat heavy for the size.