Lapis lazuli is frequently treated after it is cut and before it is sold as finished gemstones, sculptures, or ornaments. Lapis lazuli is slightly porous and that allows it to accept and hold dye. Much of the material that enters the market has been treated with a blue dye to remove the visibility of white calcite. It is then frequently treated with wax or oil that improve the luster of polished surfaces and seal the dyed calcite.