The present invention is directed to a salt optic provided with a multilayer coating in order to improve upon the moisture resistance of a salt optic, when compared to the moisture resistance of an uncoated salt optic. In one aspect, the present invention is comprised of a coated salt optic having at least a first coating layer and a second coating layer, the first coating layer being surface-smoothing layer and adhesion layer, and the second coating layer being a moisture barrier layer.