The Complete Emerald Guide

Table of Contents

  1. Emerald Consumer Information
  2. The Origin of Ancient Emeralds in Antique Jewelry
  3. Emerald References in Antique Gemological Books

Emerald Consumer Information

As provided and validated by various gemmological organizations, laboratories and the "World Jewelry Confederation CIBJO"

Care

The pointed corners of the pear and marquise cuts need to be to closely examined for durability issues. It might be recommended for such gems to be mounted in earrings, pins or pendants (rather than rings) in order to minimize potential damage to sharp points
jewellery owners have their jewelers examine prongs periodically to ensure the emerald’s security in the mount
To prevent damaging treatments do not use ultrasonic equipment nor use detergents
Common sense indicates it is not a good idea to wear an emerald ring during gardening or other intense physical activity

Treatment

The minute fissures that are found in many emeralds lend themselves to a form of treatment by humans, aimed at diminishing or masking the inclusion’s appearance
These fissures often reach the surface and may be filled with substances including oils, paraffin, resins and polymers. Assume they are unless specifically stated otherwise
Some oils, paraffin and some resins may seep out of the fissures, especially when subjected to heat or pressure. Others may oxidize over time which requires regular cleaning and re-treatments

Cut

Emeralds are the only gems that have a specific cut named after them. The term “emerald cut” is a square or rectangular outline step-cut, containing tapered corners. Many emeralds are cut this way because it orients the gem to show its strongest colour
These cuts contain large table facets through which an admirer can best view the emerald’s rich colour and its fascinating inclusion panorama
Emeralds are increasingly cut in other shapes, including round, oval, free form, pear and marquise

Clarity

Inclusions in emeralds are considered customary and expected
While emeralds with no eye-visible inclusions do exist – these gems are extraordinarily rare
Some inclusions in emerald are referred to as “jardin” (garden) and consist of networks of tiny liquid filled inclusions lending it the appearance of a lush garden
Such inclusions can also spread the light evenly through the gemstone (desirable)

Color

Vibrant green to bluish green to green
Pale emeralds are not called emeralds but “green beryls” and have a dramatically lower price. The difference is sometimes difficult to establish and often abused

The Origin of Ancient Emeralds in Antique Jewelry

Where do Emeralds in antique jewelry come from?

Emeralds are among the most prized of gemstones. Owners understandably want to know about the source of these valuable gems in specimens and jewelry. Suppose however that the emerald is set in a Gallo-Roman earring, or in a 13th Century French crown, or a sunken Spanish galleon? What clues could one find in order to deduce the gem’s history and origin without destroying the priceless object? A newly applied scientific technique from a team of French researchers may hold part of the answer (Giuliani et. al., 2000).

Ancient Emeralds Brooch
Gold and Emerald Pendant at the Victoria & Albert Museum

This technique uses oxygen isotopes within the minerals. To give a little “chemistry-lite”, most elements, including oxygen, come in several varieties, called isotopes. Isotopes differ from each other in having different numbers of neutrons in the nucleus. Some isotopes are radioactive and break down. Many are not radioactive and are called stable isotopes. The isotopes of oxygen are stable, and behavior mostly alike. You breath all of them in any one breathe. However the ones that are slightly heavier (another neutron or two in the nucleus) do behave slightly differently from those that are lighter. For example, water that evaporates from the sea has more of the light isotope in it than the heavier stuff left behind. This persists in rain water. So a mineral formed from rain water will have a different mix of oxygen isotopes in it than one that forms from sea water – or groundwater – or volcanic water. Each source of water has a slightly different identifying ratio of these oxygen isotopes in them.

So how does this relate to emeralds? Emeralds from various districts (and even mines within districts) have different oxygen isotope ratios in them – different oxygen “fingerprints”. The French geochemists measured these values for many emeralds from known localities, then compared them to emeralds whose origins were not known. Fortunately these tests require only a tiny amount of material, and are not destructive to the gem.

Their tests lead to several surprising results. The emeralds in a 17th century French crown originated from Habachtal emerald mines in Austria. An emerald in a Gallo-Roman ring best matches the emeralds from the Swat-Minguora district in Pakistan. This ring dates back to 500 BC. It was previously thought that emeralds at that time were known only from Egypt and Austria. The new findings show that trade was going to Rome along the Silk Road long ago. An emerald from a Spanish Galleon sunk in 1621 was from the Muzo area in the western emerald district of Columbia., showing how rapidly the mines developed after their discovery. An emerald from a gem treasury in India was also from Columbia, showing an influx of New World gems into Old World collections in the 17th and 18th centuries.

Ancient Emerald Crown
Imperial Emerald Tiara Commissioned by Count Guido Henckel von Donnersmarck for His Second Wife Katharina Wassilevna de Slepzoff. The Eleven Pear Shaped Polished Colombian Emeralds Could Have Been Part of the French Crown Jewels as Empress Eugenia de Montijo’s Private Collection Included Twenty Five Drop Emeralds Like These Ones That Were Sold in Auction Back in 1887

Similar techniques are being developed for rubies and sapphires. As more sources for gem and more artificial gems come on to the market, such analytical tools will be increasingly important as ways to evaluate and validate gems from a variety of sources.

Ancient Emerald Turban Ornament
A Sarpech (Turban Ornament) From the Nizam Jewel Collection

– Dr. Bill Cordua, University of Wisconsin-River Falls

Reference: Giuliani, G., et al., 2000, “Oxygen Isotopes and Emerald Trade Routes Since Antiquity”, Science, vol. 287, p. 631 – 633.

Emerald References in Antique Gemological Books

Origin of Emeralds

A reference work on Precious Stones. Large chapter on Beryls in general and Emeralds in particular.
Goodchild on ancient findings and origins of emeralds

Theophrastus on Emeralds

A native of Erressos in Lesbos he was a successor of Aristotle. He lived in the 3th century BC, and his work “On Stones” is one of the earliest available works on the different “gemstones”. Commentary on Theophrastus references to Emeralds.
Theophrastus on Emerald treatments, color and other green stones

George F. Kunz Emeralds in North Carolina

A complete and thorough overview of all gemstones found in North Carolina. North Carolina Emeralds
Several USDS reports: 1912: Beryl North Carolina and on “North Carolina Emerald Mining“. USGS 1911 report.

Prof. Oliver Farrington on Emeralds

Oliver Farrington was the curator of Geology of Chicago’s Field Museum of Natural History between 1894-1904. Farrington Gems and Gem Minerals: Emeralds

Castellani on Emeralds

Castellani was a famous Italian jeweler in the 19th century with an extensive gem collection of his own. His book serves as a reference on different gemstones. He dedicates a separate chapter to Emeralds.
Castellani Gems, Emerald Chapters

George F. Kunz: North American Emeralds

An amazing standard work of George Fredrick Kunz (VP of Tiffany). George Frederick Kunz Gems of North America, on Beryls and Emeralds

Edwin Streeter Precious Stones and Gems

Edwin Streeter was one of the more famous Victorian jewelers in London. He hired his own vessel and sailed it to go pearl fishing in the Pacific seas. He also led a consortium again Baron Rothschild for the Ruby mines in Burma. A great and extensive chapter on Emeralds and other Beryls.
Edwin Streeter: Gemstones, Emerald chapter

Emerald Treatements

Roman treatments of Emeralds
17th Century Tavernier on (non existant) Emeralds of India

Columbian Emeralds

World’s largest uncut Emerald: Patricia Emerald
Columbian emeralds found along the Silk Route !!