This is a example of light green datolite crystals that have grouped together. There are quartz crystals that are scattered across and included within the datolite crystals. The luster of the piece is low. This piece is from Charcas, San Luis Potosi, Mexico. The overall dimensions are 18 cm wide by 12 cm tall and 6 cm front to back. There is some bruising and nicks along the edges but it does not distract from the appearance.