Why Heliodor is Best Gemstone For You - Information

Most gemstone buyers are well acquainted with the most famous beryl family members - emerald and aquamarine. Some of them are also familiar with the salmon pink beryl known as morganite. But not many people are aware that there is also a lesser-known member of the beryl family, which is, in fact, the most available and affordable; golden beryl.

Heliodor is a name used by gemologists and mineralogists for specimens of the mineral beryl with a yellow, greenish-yellow, or golden-yellow colour. Also known as golden beryl, yellow beryl, or inappropriately as yellow emerald.

Pure beryl is colourless, but impurities within the mineral cause beryl to occur in various colours. The yellowish colours of heliodor are usually caused by small amounts of iron within the mineral's crystal structure.

The first major deposit of yellow-golden beryl was found by a German mining company in Namibia in 1913.

They named it heliodor from the Greek word meaning "gift from the sun" and hired a famous designer, Lucas von Cranach, to create fabulous jewellery set for Kaiser Wilhelm II and his wife.

As a result, Heliodor gained some international fame. However, it proved to be short-lived because heliodor was soon forgotten when the war intervened.

Additional deposits of heliodor have been discovered in Brazil and Madagascar, and these gemstones are now widely available. They tend to have exceptional clarity and can often be found in large sizes.

It seems the use of the term "heliodor" has declined somewhat, and there is some disagreement over the use of the terms "golden beryl" and "heliodor".

According to a well-known gemological reference (Walter Schumann, Gemstones of the World), the term heliodor refers to the light yellow-green colour of beryl.

However, Walter Schumann goes on to note that "since there is no clear distinction between yellow and green-yellow tones compared to golden beryl, heliodors are generally rejected as an independent precious beryl variety and rather are counted among the weak-coloured golden beryls".

Golden beryl is sitting on 7.5 to 8 on the Mohs hardness scale, so it is suitable for all kinds of jewellery. Golden beryl colours range from the weak yellow-green of heliodor to lemon-yellow and golden-yellow.

Several Golden beryl deposits have been found in Brazil, Sri Lanka, Madagascar, Namibia, Nigeria, and Zimbabwe.

Probably the largest cut of golden beryl in the world is the flawless 2,054-carat gemstone on display in the Smithsonian Institution Hall of Gems in Washington, D.C.

"Yellow Emerald" - A Misnomer: Some gemstone vendors often used the term "yellow emerald" while selling heliodor, which is a misnomer meaning (a wrong or inaccurate name or designation).

The name "emerald" represents a green variety of beryl caused by chromium or vanadium. By definition, emeralds have a green colour. The name "yellow emerald" is misleading because it associates a less expensive heliodor with a more expensive emerald.

The Federal Trade Commission (FTC) publishes a set of Guides for the Jewelry, Precious Metals, and Pewter Industries in 2010stating that "it is unfair or deceptive to describe a product with an incorrect varietal name".

The names "green amethyst" and "yellow emerald" will be held up as examples of names that could be misleading "based upon consumer perception".

Physical Properties of Heliodor:

Chemical Classification

Silicate

Chemical Composition

Be3 Al2 Si6 O18

Colour

Yellow, greenish-yellow, golden-yellow

Mohs Hardness

7.5 to 8

Specific Gravity

2.6 to 2.8

Lustre

Vitreous

Diaphaneity

Translucent to transparent

Streak

Colourless (harder than the streak plate)

Cleavage

Imperfect

Diagnostic Properties

Crystals are prismatic hexagons with flat terminations and without striations. Hardness and relatively low specific gravity.

Crystal System

Hexagonal (occurs in prismatic to tabular crystals), often etched.

Uses

Gemstones for jewellery and collectors. Specimens for mineral collectors.

Heliodor Physical Properties and Gemology: Heliodor with good clarity and rich colour can often be cut into attractive shapes and sizes. Its hardness of 7.5 to 8 enables it to stand up well to abrasion. Making it a suitable gemstone for rings, earrings, pendants, pins, bracelets, and almost any other jewellery use.

The demand for heliodor is small as compared to other beryl gemstones such as aquamarine (a blue to greenish-blue beryl), emerald (green beryl), and morganite (an orange to pink beryl).

The jewellery-buying public is not familiar with this gemstone. It has only been used in limited amounts in commercial jewellery because a steady supply of calibrated stones has not been developed in large numbers.

As a result, heliodor is rarely seen in the gemstone market or jewellery stores. However, it is more likely to be found in online or designer shops and stores specializing in interesting gems and jewellery. Heliodor is a popular gemstone with gem collectors, and well-formed crystals with good colour are popular with mineral collectors.

Beryl Var. Heliodor © Crystal Classics Fine Minerals Limited

Gemstone Treatments: The iron contained in heliodor can be altered by heat treatment. Light heating will sometimes improve the yellow colour of a gemstone.

In some gemstones, further heating will transform yellow heliodor into a greenish-blue to blue material.

If the colour is appropriate, this material will be sold as heat-treated aquamarine. The colour of some yellow heliodor can also be improved by irradiation. Irradiated heliodor is common in the marketplace.

Cat's-Eye Heliodor: Rare heliodor specimens contain a "silk" of tiny, straight and parallel, needle-shaped inclusions. When this heliodor is faceted into a cabochon with the silk oriented parallel to the flat bottom of the gemstone, the dome of the gemstone will exhibit a phenomenon known as cat's-eye or chatoyancy.

The most desirable chatoyant beryls have a highly attractive body colour and a bright, thin eye that perfectly bisects the gemstone. These gemstones must be cut by a highly skilled person, who can determine the silk orientation within a piece of rough, then cut a gemstone that best displays a well-centred cat's-eye.

Heliodor cost: The absence of greenish and brownish tones greatly increases the cost of heliodors. Minerals of bright yellow tones, which are rarely present on the shelves of jewelry stores, are most valued. Ordinary tan stones are not very expensive. You can buy heliodors of this category at a price of several tens of dollars per carat. Natural stones rarely have internal or external defects. In this regard, even small inclusions and cracks greatly reduce the cost of stones. Large stones of the highest jewelry quality and golden yellow colour can reach $ 60-120 per carat.