Program Speaker
Paul Hlava: Emerlds Part 2

by Nancy L. Attaway

Vice-President/Programs Paul Hlava presented his talk on “Emeralds, Part 2.” In Emeralds, Part 2, Paul discussed the history, lore, and the important parts emeralds played in world history. Paul explained the cutting of emeralds, the known treatments, the methods of emerald synthesis, emerald substitutes, and the inclusions in emeralds. He remarked on the costs of emeralds and the factors influencing cost, along with the recommended care of emeralds.

Paul stated that emeralds were nearly as old as civilization itself. He began his emerald story in ancient Egypt around 3500 B.C. and cited the Mines of Cleopatra. Egyptians mined emeralds in the desert hills of the Sikait-Zabara region between the Nile River and the Red Sea in southern Egypt. Paul said that Cleopatra’s emerald mines had a long history, as the Egyptian miners unearthed emeralds in the region for over 3,000 years. The Romans mined emeralds there as well and produced the most gems during their occupation. Examples of jewelry set with emeralds have been unearthed from ancient Egyptian and Roman times.

The Turks and Arabs later worked the mines until the 13th century, and the mining area was all but abandoned during the 1700’s. The location of Cleopatra’s emerald mines became lost for a time and was thought to have been refound in 1816. Smaragd is the old name for emerald.

During their empire expansion, Roman legions moved north and discovered an emerald deposit in the mountains of Habachtal, which is now Austria. Marco Polo reportedly carried emeralds back to Italy with him from his epic journey to China at the end of the 13th century. Likewise, the Crusaders returned from the Middle East with emeralds. India stood as the world’s leading gem market for thousands of years, and Indians valued large, fine emerald crystals. Paul said that it is now certain that Egypt established the oldest and most worked emerald mines in the ancient world. However, chemical analysis performed in the late 20th century revealed that the emeralds thought to have been from Egypt were actually from certain areas in Austria, Pakistan, and Afghanistan. And, much of the stones that were believed to be emeralds from Cleopatra’s mines were later discovered to be green beryls. Paul reminded us that emeralds are colored by chromium or vanadium (or both), and that green beryls are colored by iron.

Paul explained that many medicinal cures were attributed to emeralds. Emeralds were reputed to be able to neutralize poisons, cure dysentery, cool a fever, stop bleeding, assist in the delivery of babies, cure bad eyesight, and ward away snakes. Some folks even thought that emeralds could foretell future events and improve one’s memory. Emeralds were held in very high esteem by ancient people, and the value for emerald continues in the world gem market today.

Paul said that native people in Colombia used emeralds in jewelry and in religious ceremonies 500 years before the Spanish conquest of the America’s. Paul remarked that Pizarro’s men were reputed to have broken many fine emerald crystals, thinking that an emerald was hard enough to sustain a blow from a hammer. In their constant quest for gold, the Spanish brought back many fine emeralds from the New World and then traded them to the royals in India, Europe, and Persia for gold, diamonds, and pearls. Paul stated that the Spanish were responsible for the dramatic increase in the trade of emeralds during the 1500’s, largely through the amazing emerald supply found in Colombia. Paul mentioned the Atocha emerald cross, and that the ship carrying it and other emeralds sank off the Florida coast in 1622, only to be found by Mel Fisher in 1986.

Paul said that all green gems found in Brazil were known as “Brazilian emeralds” until the 19th century, when emeralds were distinguished from green tourmaline. The term “Brazilian emeralds” refers to green tourmaline. During the 20th century, emeralds were found in Africa, Pakistan, Afghanistan, Russia, and North Carolina. Paul explained that the deposits in Afghanistan were actually re-discovered in the 1970’s, having been lost for a time.

Paul discussed the logic behind emerald cutting. Beryls cut rather nicely, he said, but emeralds are more difficult to cut, due to their inclusions. Emeralds are usually faceted to show off their fine green color and not necessarily cut to show fire and brilliance. Emeralds are often cut with very deep pavilions to maintain carat weight, and, thus, increase their per carat value. Paul said that you can get bluer stones by cutting the crystal perpendicular to the C axis.He said you can get more saturated, yellow green stones by cutting parallel to the C axis. The rectangular “emerald cut”, the square, and the octagonal shapes are the most common shapes used in faceting emeralds. These particular shapes best accommodate the natural crystal outline of the rough emerald crystal to retain the most carat weight and value.

Paul remarked that ovals and pearshapes are also common, in that their yield from the natural crystal shape of the emerald is good. Cutters usually go for maximum yield on emeralds to retain the most carat weight and get a better price on the finished gem. Calibrated stones are not really normal for emerald, in that emeralds are rare and yield certain shapes better than others. Rounds, marquises, and heartshapes are very unusual to see in cut emeralds.

Paul said that emeralds can be cut en cabochon in rounds and ovals, like the magnificent cabochon-cut emeralds set in the famous Topkapi Dagger. Emeralds are also carved, and Paul mentioned several famous carved emeralds, like the 217-carat Mogul Emerald. Famed Canadian gem carver Thomas McPhee carved a large emerald crystal years ago that represented historical figures related to Canada’s history. The gem was estimated at over $2 million.

In discussing treatments, Paul remarked that the good news was that no heat-treatments or irradiation is ever used on emeralds. The bad news, he said, was that oiling is used on both rough and faceted stones. Impregnation with plastics is also used, as well as dyes. Terms describing synthetic emerald include “man-made”, “lab-grown”, “cultured”, and “created”. Paul said that synthetic emeralds contain the same chemistry and properties as natural emeralds.

Paul stated that emeralds cannot be made by flame fusion, nor by the Verneuil process. He said that synthesized emeralds are flux-grown. The flux-grown process involves molten chemicals in a platinum crucible. A crucible is placed in an oven at high temperatures (1200 degrees Centigrade or higher). Emeralds are also grown hydrothermally, where solid chemicals are placed in pressurized vats at medium temperatures (600 degrees Centigrade or higher) for months. Emeralds can also be made through the chemical vapor deposition method, which has chemicals bled into a vacuum chamber and deposited on a hot substrate.

Paul stated that Carroll Chatham was the first person to synthesize emeralds (in 1935). (It is thought that he died from beryllium poisoning.) Paul listed the synthetic emerald manufacturers. Flux-grown emerald producers include: Bijoreve /Seiko; Chatham; Gilson/Nakazumi; Inamori; Kyocera; Lechleitner; Lennix/ Lens; CIS; and Zerfass. Hydrothermal emerald growers include: Biron/Biron Minerals (previously Pool); Lechleitner “overgrowth”; Quintess/Linde; Regency/Vacuum Ventures; and CIS. Those manufacturers of created emeralds by the chemical deposition method are ANICS/Adachi Shin.

Paul also listed the various emerald simulants and said to beware of fakes. Green glass is used as an emerald substitute, which started in antiquity and still continues, of both cut stones and crystals. Paul said to look out for doublets and triplets, coated stones and foil-backed stones, fractured and dyed stones, hollowed-out beryl crystals filled with green-colored plastic, manufactured emerald crystals glues on matrix, green-colored synthetic spinels, green cubic zirconia, tsavorites, chrome tourmalines, some peridot, chrome diopside, green colored plastic, and more. Paul believes that disclosure is very important in selling emeralds. Oiling is considered dishonest if not disclosed.

Paul explained that emeralds are usually included, often richly included. These inclusions are the consequence of stress, where chromium atoms enter the aluminum site in the beryl crystal's atomic lattice. Chromium atoms can break the atomic lattice bonds of emerald, because the chromium atoms are larger than the spaces in the atomic lattice. Paul said that even synthetic emeralds contain inclusions. Inclusions, known as “jardin”, are considered part of the “charm” of emeralds. “Jardin” is French for garden; a garden of inclusions. Paul remarked that inclusions often provide clues to the origin of the emerald, and, consequently, inclusions in emeralds are much studied.

Paul explained that inclusions are all the things found in a cut stone that keep it from being perfectly clear, with the exception of color and color zoning. These include fractures, cavities, crystals of other minerals, and dirt. Cavities may be empty, fluid-filled, fluid and vapor filled, filled with fluids, vapors, and with one solid or more.

Paul stated that inclusions offer the best clue to the origin of the stone. Inclusions can even determine whether an emerald is natural or synthetic. Certain inclusions are indicative of certain mines or mining districts. Certain inclusions in synthetic emerald provide evidence of the method used in its manufacture. Mineral inclusions include: carbonates (like the parasites found in Muzo emeralds), micas, oxides, sulfides, and silicates. Paul said that pyrite was a common inclusion found in emerald. There are both two-phase inclusions and three phase inclusions in emerald. Metals may also be inclusions in emerald, like the platinum platelets found in flux-grown emerald.

Paul mentioned the cost and factors associated with emeralds. He said that emeralds are precious and rare. Therefore, they command a high price. Paul explained that emeralds are priced per carat and can run hundreds of dollars per carat for medium grade emeralds to thousands of dollars per carat for fine emeralds. Factors that determine the value of an emerald depend upon depth of color, clarity, jardin, size, cut, and origin. Colombian emeralds provide the benchmark of comparison for fine grade emeralds.

Paul ended his talk on emeralds with the care of the gem. He said that emeralds are hard but brittle. Emeralds can be highly flawed, where the crystal structure is stressed. He said to avoid mechanical shock and thermal shock. Paul warned to never clean an emerald in an ultrasonic and to never steam clean an emerald. Instead, Paul advised using warm water, a mild detergent, and a soft brush to clean an emerald. He also said to store emerald jewelry separate from other jewelry to avoid scratching the gems. Over time, emeralds can dry out and show more inclusions, and Paul said that emeralds can be re-oiled.

Paul delighted his audience with slides of beautiful emeralds in marvelous jewelry creations. Paul is a fountain of knowledge on gems and minerals. Everyone thoroughly enjoyed his well-prepared talk on emeralds. Thanks, Paul.

{Editor’s comment: Please see the two excellent books on emeralds by noted author and photographer Fred Ward for more information. Also, please see the Summer 1999 Issue of Gems and Gemology on “The Identification of Various Emerald-Filling Substances”. And, please see the Winter 1999 Issue of Gems and Gemology on “Classifying Emerald Clarity Enhancement at the GIA Laboratory”. The book, Emeralds and Other Beryls by John Sinkankas is a classic reference to have in your library.}