Beryl is a most alluring and popular mineral. It occurs in a diversity of colors, and has several important gemstone varieties. The green variety, Emerald, is one of the most precious gems. Only green Beryl with a deep green color is called Emerald; light green Beryl is simply “Green Beryl”

Green Beryl from certain localities can be heat treated to produce sky-blue Aquamarine. Other popular gem varieties of Beryl are the pink Morganite, and the yellow Heliodor and Golden Beryl. A deep red variety of Beryl, known as Red Beryl is extremely rare, and only comes from two localities in Utah. When in good specimens, Red Beryl commands an outstanding premium and is very difficult to obtain.

Pure Beryl is colorless. However, a wide range of impurities cause the diverse amount of colors and many varieties. The green color in Emerald is usually caused by traces of the element chromium, and the blue color of Aquamarine usually by iron.

Beryl is naturally transparent, however inclusions and impurities may make it opaque. All gemmytransparent varieties are highly valued, but the other forms of Beryl in opaque crystals are much more common. Some of the largest natural crystals known are of Beryl, with enormous crystals having been found in several pegmatite occurrences.

Beryl often crystallizes in perfect, six-sided hexagons. Crystals are usually as individual prismatic hexagons. Crystals may be enormous in size; some 30 foot long (8 meter), well-crystallized examples have been found. Beryl may also be short, stubby crystals, and occasionally in tabular crystals and plates.

The bases of Beryl crystals are usually flat; pyramidal terminations are rare. Also occurs in columnar aggregates, in distorted etched crystals, and massive. Occasionally in drusy or platy aggregates and as bundles of thin, long crystals. Crystals may be striated lengthwise.