Beryl In All Its Forms

 

Beryl is a gemstone variety, which has several family members. 

The basic chemical formula for Beryl is a complex mix of Beryllium (its main component, giving its name and the description of green) with Silicone, Oxygen, Aluminium and then some other rare earth minerals. These earth minerals cause the differences in colour. Each differing colour/colour range has its own name. 

 

Emerald

The first of this family is probably most widely known and treasured of the big 3 coloured gems, Emerald, Ruby, and Sapphire. Ruby and Sapphire are in face Corundum, a different gem altogether, with a different chemical formula. They are, however, essentially the same main minerals of Aluminium and Oxygen with trace elements that change their colour.

All types of Beryl grow in a hexagonal crystal structure and most often occurs in long columnar crystals. Emeralds differ slightly from its siblings in that the environment is different for its growth. Most often the crystals are a result of the metamorphic process. Where tremendous heat and pressure pass through hydrothermal veins, the elements mix through this process, collecting the rarer elements of Beryllium and/or Chromium and Vanadium, giving the richly desired green colour.

The crystals also cool, this process often means that the resulting crystals are often naturally included with foreign material, liquid, solid and gas inclusions. In rare cases these inclusions can contain all three of these occurrences called three phase inclusions. Whereby a natural void within the crystal will contain a liquid, a gas bubble, and a solid crystal. The natural flaws in Emerald are most often visible to the naked eye, in the form of feathers, milkiness, or mineral inclusions of other material. The formation process means that high clarity stones are highly unlikely, incredibly rare, extremely highly prized and valued.

The nature of Emerald, the way it forms, and the resulting crystals means it is not a stone that reacts well to heating, which is why it is never done to Emerald. Instead, treatment of these stones is that they can be “oiled”. This is where pressure injected oils into natural surface reaching fractures can be done, mainly to improve apparent clarity. These are detectable in labs and by highly skilled professionals with high magnification and experience, however cutters do use liquids such as baby oil during the cutting and polishing of Emeralds to stop burning of the facets from friction during this process.

Most Emeralds will have to some degree of oil present, even certificated Emeralds will state whether an Emerald has minimal, medium, or high levels of oiling. The higher the levels of residues, generally the lower the quality of the original stone and its resulting lower value. 

 

 

Aquamarine 

Aquamarine the next largest and prized of the Beryl family. Also, a mix of Silicone, Aluminium and oxygen, with then the addition of Iron being the colour causing agent for this stone. Its growing environment is very different to its sibling Emerald. Where high pressure and heat traveling through schist rock results its naturally included material.

Aquamarine like many others of this family form in Pegmatites. With small or large pockets of liquids and rare earth elements as a core. It is surrounded by a casing of hot magma rising too close to the surface of the earth. As these pockets slowly cool from the outside in, the resulting cooling over a long period of time enables the larger Beryl crystals to form and grow in a slower more controlled environment. This greatly slowed process allows virtually unflawed crystal formation to happen, resulting in the more typically eye clean Aquamarine stones that consumers expect.

The largest of these on record ever found weighed 110kg (244lbs) and measured 48cm (19”) long and 38cm (15”) in diameter. Although large Aquamarine crystals are not that uncommon, such large stones are very difficult to use in jewellery. There is less demand for sizes above 25 carats. However, some fantasy stone cutters make great use of these larger crystals to create amazing stones from such high clarity specimens or may even create fantastical sculptures from them. The most important thing to note difference wise, is that the general appreciation in the trade is that bluer tones for Aquamarine is the industry wide preference.

These stones are most often the result of heat treatment. Naturally coloured Aquamarines have a greener tone. If you want a more natural stone, look for the greener colour stones as there is less likelihood is has been subjected to this form of treatment.

 

 

Pink Beryl/Morganite

Pink Beryl otherwise known in the industry as Morganite. Again, the same main elements, but with the addition of trace elements of Manganese.

Due to distinct pleochroism - different predominant colours visible dependant on viewing direction of the crystal structure. Often pale pink in one direction and deeper violet in the other. it is necessary to carefully orientate the rough for fashioning the final cut stone and resulting colour. Morganites are rare and gems usually must be fairly large to achieve the finest colour.

The resulting normal peach colours of Morganite by collectors is most likely unheated, where a lot of material is heated to achieve pinker stones. Again, it is due to the same formation circumstances as Aquamarine and the naturally forming imperfection free crystals. The violet stones are achieved by carefully considered by the cutting direction of the original rough, where a truer natural highly saturated violet colour has been achieved in a smaller stone, rather than compromising its colour for size. 

 

 

Yellow Beryl/Golden Beryl/Heliodor

Yellow or Golden Beryl sometimes called Heliodor, traces of Iron cause its yellow colour, which can sometimes have an orangish or greenish tint.

Also forming under the same circumstances as Aquamarine its much rarer than this sibling, but unfortunately it never received the same popularity. Meaning it’s never been as prized nor considered as valuable as high-quality Aquamarine.

It does boast the same typically high clarity forming rough, and although it can form in large enough crystals to achieve beautiful carvings, it never forms as large as Aquamarine. It’s brightness however means it’s ideal for designer and fantasy cuts.

Heat treatment of this stone can sometimes result a more marketable Aquamarine colour with about the same resulting intensity as the original yellow colour. But due to its unpredictability other stones can become a lighter yellow colour, while still others turn a blue so pale that the resulting stone would have been more valuable if it had been left its original colour. 

 

 

Green Beryl

Green Beryl, the difference between this and Emerald lies in the difference in tone and saturation levels. Also, the trace elements causing the colour.

Where Emerald is principally coloured by Chromium, and sometimes Vanadium (this causes the much more highly desirable blue tones found in Columbia Emeralds), Green Beryl is coloured principally by Iron with perhaps some Chromium. Its colour can be blueish but most likely has a yellowish tone to the green, but with heat treatment turns blue-green and tends to become a more yellowish green with radiation.

Again, the same slow formation process of this stone, gives high clarity and the possibility of the heat treatment process. However, the presence of the Chromium prevents complete removal of the green colour and heat treating of this material cannot create a dominant blue colour as it can with Aquamarine.

 

 

Red Beryl

Finally, the rarest of all the Beryl family is the ever-elusive Red Beryl sometimes referred to as Red Emerald, but this name has been largely dropped due to confusing customers, as Emerald is always known as being a green colour.

It’s often a highly saturated pure red colour, sometimes called a raspberry red. Stones commonly have pleochroic shades of purplish red to red to orangish red. Colour depends on concentration and valance state of Manganese along with other trace elements in the gems structure. Stones cut perpendicular to crystals length are more purplish red. Red Beryl’s are generally transparent like its siblings of Aquamarine, Morganite, Yellow Beryl and Green Beryl due to its growth conditions. But it can be translucent if they are highly included, like its other sibling Emerald. Two phase inclusions and fingerprint inclusions, unsealed fractures, solid inclusions, distinct colour zoning and growth features can occur.

Like Emerald does not respond well to heat treatment. Unlike all its siblings though, Red Beryl is most often cut in melee sizes, small stones that very often are no more than around 0.15 of a carat for final cut stones. This is partly due to its intense colour showing best in small sizes and it naturally only forms in small rough crystals, the largest ever Red Beryl recovered was reported to measure 14x34mm and weighed about 45cts. The largest ever cut stone weighed just over 8cts. The final thing that limits this beauty of a stone, is that it has only ever been mined in the Wah Wah Mountains in southwestern Utah. Mining of this stone at its peak yielded only 0.50cts to 0.80cts of facet grade rough from 1 ton of rock.  In 1990 the mine produced only 200 stones larger than 0.25cts. Due to such limited production the 1 and only mine closing in the early 2000s. Since then, this rarely seen gemstone has become an expensive speciality collectors stone. 

 

If you would like any more information on Beryl, please do visit us in our showroom and we can show you some of our products in the flesh. If you would like a piece of bespoke jewellery made with one of the above gemstones being a feature, please feel free to contact our in-house jewellery designer Tony. He will be able to order some stunning stones into the showroom so you can see exactly what colour you will be getting. Talk about getting the perfect stone!