The Guide For Buyers & Investors
In the gemstone universe, natural emeralds and their signature lush green color are the benchmark for all green gems. They are prized as much now as they were thousands of years ago. Emeralds are a form of beryl, a mineral that also comprises aquamarine and assorted colored beryls. The most coveted type of emerald are those that fall in the color range of bluish green to pure green accompanied by a strong to vivid saturation and medium to medium-dark tone. Color is the most important consideration for determining the value of a natural emerald, assuming all else is the same.
At Diamond Envy, our natural emerald knowledge can be credited to a hands-on approach. Experience with gems in all colors and sizes gives us the best reference for evaluating the emeralds selected for our collection. Our in house gemologists assess each stone for cut, color and clarity to ensure we feature only the best conflict-free, natural emeralds. Our natural emerald collection comprises loose stones and jewelry featuring high quality Colombian and Zambian emeralds. To learn more about these beautiful gems, read below for information regarding emerald price, color, value and history.
Color
Color, consisting of hue, tone and saturation, is the foremost basis on which emerald value is established as long as other properties of the emeralds are identical. Even a very minor disparity in color can have a marked effect on the emerald’s value.
The most valuable natural emeralds will be bluish green to pure lush green in a strong to vivid saturation and of medium to medium-dark tone. These same emeralds should also exhibit high transparency and even color distribution. Any color zoning should not be apparent to the naked eye. Any hue that leans too yellow or too blue is not considered emerald but rather another type of beryl, which means such a stone does not have the same value as an actual emerald.
Natural emeralds derive their color from trace amounts of the elements chromium, vanadium and iron. Specific amounts of each, or lack of, will result in particular hues, tones and saturations. By and large, the more chromium or vanadium in an emerald, the greener the stone will be. The more iron in an emerald, the bluer that stone will be. A natural emerald that has a large amount of iron will be bluer green in color while an emerald with a small amount of iron will be a more lush green.
Cut
In their unrefined state, emeralds are usually a six-sided crystal prism found in regular shapes with qualities that are more or less constant and a negligible quantity of cleavage (an internal crack or break in a gemstone.)
The cut of choice for emeralds is the highly regarded emerald cut. The emerald cut is a step cut that features a large rectangular or square table and beveled corners. The facets in the crown and pavilion will have an exact parallel alignment in emerald cuts that are expertly executed.
Natural emerald can be cut into round, cushion, oval, pear, heart and marquise shapes as brilliant, step and mixed cuts. Those stones containing large unavoidable inclusions are routinely cut into cabochons. Cabochons that feature a star-shaped formation of inclusions are known as trapiche emeralds – trapiche means “sugar cane mill” in Spanish, in which miners of this type of emerald observed a likeness to the gears of the mills.
Challenges Facing Emerald Cutters
Cutters must keep in mind several concerns when contemplating how to cut a natural emerald. Amid their deliberations, they must determine how to work with the rough emerald’s color, durability and inclusions. Any errors in decision-making can considerably diminish the weight of the emerald and, in turn, the impact on the value of the polished emerald.
There are four properties of natural emeralds that present an inherent challenge to cutters:
- Nearly all natural emeralds feature prominent fractures, or fissures, that make it necessary for cutters to fashion the emerald into a cut that will marginalize the presence of the fractures.
- The characteristic fragile nature of emeralds means they are particularly prone to breakage while being cut, polished and set in jewelry. In fact, emeralds are so delicate that they can break merely by being mishandled when worn on a regular basis. This is where the emerald cut provides the ideal solution – the faceted cut corners act as a buffer against forceful blows while jewelry prongs protect those corners.
- The essence of an emerald is its color. Thus, the cutter needs to execute a cut for the rough that will capture the stone’s optimal hue, tone and saturation. This can be done by fine-tuning the stone’s proportions and either removing or adding facets. A light-colored emerald can be made darker by achieving a deep cut and reducing the size of the table and amount of facets. A dark emerald can be lightened by making a shallow cut and enlarging the size of the table and amount of facets.
- The tendency to display more than one color (“pleochroism”) of natural emeralds, which usually fall in the bluish green to yellowish green range, obliges the cutter to position the stone’s table to sit perpendicular to the length of the stone. This position will result in the bluish green color that is universally beloved and highly prized.
Clarity
It is a widely accepted fact that just about all emeralds have inclusions that can be seen by the naked eye. This unavoidable condition merely underscores the hefty value of natural emerald that is completely eye-clean. The extent to which emeralds contain inclusions can be divided into three groups: (1) lightly included; (2) moderately included; and (3) heavily included. Inclusions that are typically encountered in emeralds are fractures, needles, crystals, liquid inclusions, as well as two- and three-phase inclusions. Two-phase inclusions have a liquid and a gas. Three-phase inclusions have at least one crystal, a liquid and a gas. The inclusions that occur most frequently in natural emeralds are fractures and liquid inclusions.
It is not uncommon for natural emerald inclusions to be likened to moss or a garden – in fact, “jardin,” which means garden in French, is occasionally used to describe emeralds that have such characteristics. As with other colored gemstones, clarity usually determines the stone’s transparency and value – exceptions are largely made for first-rate emeralds that have inclusions visible to the naked eye. It is only when the inclusions in the emeralds significantly interfere with clarity and transparency that they will have a negative impact on the value of the stones.
Size
Finished emeralds set in jewelry can be found in all sorts of sizes, from the very small (1mm to 5mm weighing 0.02 carats to 0.50 carats) to those that are much larger, weighing at least 15 carats. However, natural emeralds can weigh as much as hundreds of carats – such rare and expensive gems are routinely reserved for museums or cherished as part of a private collector’s trove.
Zimbabwe’s Sandawana emerald mine is famous for its production of very small but very rich gems. Cut emeralds from the Sandawana mine can be as small as 1mm square yet they will nonetheless possess a noticeably vivid green hue. The average for emeralds emerging from this mine is between 0.05 carats to 0.25 carats.
As is the case for all precious gems, as the size of the emerald increases, so, too, does its price, assuming all other properties are the same. While a 3-carat emerald may be just three times the weight of a 1-carat, both of comparable quality, the monetary value of the 3-carat emerald will be considerably more than merely three times the value of the 1-carat emerald.
Treatments
The purpose of treating an emerald is to reduce the obvious presence of fractures where they reach the surface. Emerald treaters rely on an assortment of oils and resins to fill fractures in natural emeralds. At times, they will compound both oil and resin to form a hybrid filler.
When oil is used to fill fractures, the process is informally referred to by some within the emerald trade as “oiling.” Possible oils used as fillers include palm, cedarwood, corn, linseed, lubricating, mineral, olive, soy and tung. As useful as oiling may be, the result is not usually permanent. When the existing oil has more or less dissipated, the emerald can be steeped in a substance that is capable of dissolving oil, such as alcohol, which will then rid the stone of the oil and make it ready to be oiled once again. For this reason, oiling is considered by many as the superior method of filling.
Emerald price is based on many things combined. As expected, untreated emeralds are highly valuable and compel buyers to pay top dollar. Assuming all other properties are the same, an untreated emerald will always have greater value than a treated one. While emeralds that have undergone minor treatments will not experience a significant drop in value, those with major and even moderate treatments will. All properties being the same, a natural emerald that has undergone major treatment will see a considerable reduction in value and price compared to an emerald that has had minor treatment.
Based on trade estimates, at least 90 percent of emeralds are treated to some degree. To keep the filler intact and prevent the already fragile emerald from further possible breakage, the best way to clean the stone is by gently scrubbing it with warm soapy water. Using anything else can ruin the emerald’s beauty.
Value
Natural emeralds carry the greatest cachet – and thus worth – of all green gemstones. The green color of an emerald sets the bar for other green stones and determines the value and price of the emerald itself. Factors that all have an influential hand in establishing the price per carat of emeralds consist of the following ideals: type of color (bluish green to pure lush green in a strong to vivid saturation and of medium to medium-dark tone); even distribution of color; minimum of inclusions; high transparency; carat weight; and degree of treatment.
Origins
Most of the world’s natural emeralds come from Colombia, Zambia, Brazil and Zimbabwe. The United States and Japan buy the most emeralds, making up 75 percent of all global consumption. Colombia has always supplied the best quality and greatest number of emeralds to the world’s markets. The best Colombian emeralds are the prototype for emeralds everywhere.
The classic Colombian emerald mines are Muzo, Chivor and Coscuez – while emeralds from these sites may have slight variations in color, they all have in common the strong lush color that makes them famous. Muzo produces emeralds that are a vivid lush green as well as bluish green. Chivor bears emeralds in a bluish green hue and Coscuez’s emeralds are a richer green that has been termed “green fire.”
The second largest supplier of natural emeralds is Zambia. Although emeralds were unearthed in the country as early as 1931, it wasn’t until 1967 that emerald rough was first mined. Unlike the six-sided prism that defines Colombian emerald rough, the emeralds of Zambia have a characteristic irregularity to their shape. They usually have a darker tone and lean more bluish green compared to Colombian emeralds. Assuming all other properties are the same, a Zambian emerald that is slightly blue will have a higher value than one that is bluer. While it does not at all detract from their beauty, the color of Zambian emeralds do not have the same rich intense color that Colombian emeralds are widely known for.
The emeralds of Brazil tend to be more commercial grade with fine quality production resulting sporadically. Their color lacks the rich intensity that Colombian emeralds have, instead occurring in a light to medium green range. They are usually bluer than Colombian stones, indicating a larger presence of iron.
Overall, African mines tend to yield natural emeralds with the least amount of fractures. The majority of African-sourced emeralds, an estimated 80 percent, are commercial grade while approximately 5 percent are high-end quality. Commercial grade African emeralds are routinely manufactured into standard-size shapes such as rounds and squares.
Zimbabwe’s Sandawana mine has been in production since 1956 – at the time the country was named Rhodesia. Sandawana has experienced steady output for the last two decades. Tiny but highly saturated emeralds are this mine’s signature yield. Despite their 1 mm size, they nonetheless materialize as a vivid yellowish green to green color, which is credited to a high level of chromium and low level of iron.
Other countries that produce natural emerald, albeit to a limited extent, include Afghanistan, Australia, Pakistan, Russia and the United States.
History
According to some historical theories, emeralds were mined by the Egyptians as far back as 3500 BC. Egypt was the leading producer of emerald prior to the sixteenth century. At the start of the sixteenth century, Europe was introduced to the prosperity of emerald mines located in the country now known as Colombia, located on the continent of South America, via the Spanish conquistadors. To this day, Colombia is the world’s top source for emerald rough. Natural emeralds were considered so sacred that the Incas appropriated them as religious sacrifices. The Incas went to extremes to safeguard their precious gems by submitting themselves to torture and even death at the hands of the Spanish but all to no avail as the conquistadors ultimately tracked down the origins of their stones.
Throughout history, Colombia has been the top provider of the finest quality, as well as the largest quantity, of emeralds. The country has single-handedly dominated the rough emerald trade for hundreds of years to the present day.
Famous Emeralds
Hooker Emerald: at 75.47 carats, the high-clarity Hooker Emerald is set in the center of a brooch designed by Tiffany & Co. that also boasts 13 carats of diamonds. It was unearthed from a Colombian mine in either the 1500s or 1600s. Once a cherished member of the Ottoman Empire’s crown jewels, as of 2010, it is on display at the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals at the Smithsonian Institution in Washington, D.C. The emerald brooch was donated to the museum by its owner, philanthropist Janet Annenberg Hooker, for whom the stone is named and had a value of $500,000 in 1977, the year the gift was made.
Devonshire Emerald: weighing in at 1,383.93 carats, the Devonshire Emerald ranks among the largest emeralds in the world. An uncut emerald, the Devonshire emerged from a mine in Muzo, Colombia. Named after William Cavendish, the 6th Duke of Devonshire, the stone was transferred to his ownership in 1831 when Emperor Pedro I of Brazil gave or sold him the stone. The Colombian emerald was put on display at the Natural History Museum in London in 2007.
At Diamond Envy, we offer an impressive selection of emeralds and jewelry. Whether you’re interested in a loose natural emerald for investment purposes or unique, handmade jewelry to give as an extraordinary gift for someone special, shop our natural emerald jewelry collection today.