Neptunite is a relatively recent mineral, having been first discovered only in the early 1900’s. Much of the Neptunite crystals from San Benito Co., California. The typical sharp contrast between black Neptunite on a white Natrolite matrix makes a very aesthetic mineral specimen. As sharply-formed, prismatic crystals with a square cross-section and distinct, pointed termination. Crystals sometimes intersect on an angle, and they may be doubly terminated. Occasionally also in thin, tabular crystals and in columnar aggregates.