Emerald is a variety that belongs to the gem species known as beryl. The species also has other variety members that may be familiar to you as a jewelry collector- such as aquamarine and morganite. These three variants of beryl, though different in color, all have good presence in the gemstone trade today, but there is also one more that is sometimes not as widely known.
The golden beryl sometimes known as heliodor, is said to take its name from the greek phrasing for "Gift from the Sun". This beautiful variety can be incredibly eye-clean in most mid-level market products. Above is a designer-cut golden beryl by famed gemstone cutter; John Dyer (photo credit). Many gemstone carvers and jewelry designers love using golden beryl in large sizes as centerpieces for their illustrious creations.
There exists some ongoing debate as to the usage of the term "golden beryl", some people say that only deep yellow-colored beryl should be called golden beryl, while greenish yellow beryl should be called heliodor. For many gemologists however, golden beryl and heliodor are usually mentioned synonymously in reference to all yellow colored beryls.
Golden beryl gets its color from the presence of Fe3+ ions in its composition. Iron is a frequent cause of color in many gemstone species and varieties, including heliodor's close relative- aquamarine. Different charges and surrounding elemental chemistry can allow for very different colors to manifest in a stone. The yellow of golden beryl can be quite saturated, but most commercial qualities may appear pastel to pale in color, with obvious hints of greenish overcast.
Citrine is much more widely known compared to heliodor. It's affordability and general supply make it the trade's staple for yellow gemstone material. Most citrine however is the product of heat-treating amethyst from Brazilian sources. On the other hand, while heliodor can also be enhanced / treated, some of the finer-quality specimens can have a natural color profile that appeals to certain collectors searching for more candidly colored precious gemstones.
Heat treating heliodor to high enough temperatures can also change its color to a bluish or greenish-blue hue, altering its variety to aquamarine. These stones are often marketed as heat-treated aqua's on the gem markets of brazil, where much of the material is sourced.
Golden beryl is somewhere in the middle of the price spectrum for yellow gemstones. Below it, you have citrine (yellow quartz) and some variants of chalcedony. Above it, you have deep colored golden topaz, and natural yellow diamonds even further up the ladder. It currently sits as one of those affordable, yet beautiful natural gems that maintains a good place in any collector's jewelry box, but is still less popularly known compared to its other relatives in the beryl family. This may change however in the upcoming years, as many kinds of colored gemstones are gaining more value and recognition worldwide.
