Hiddenite, North Carolina:
A New Source for Gem-Quality Emeralds

By Antoinette Matlins, PG

Located in the rolling foothills of the Appalachians, among the oldest and most weathered part of the mountain chain, Hiddenite, NC, has long been associated with a wide range of minerals, including emerald, ruby, sapphire, and the rare, deep green member of the spodumene family known as hiddenite. Yet there has never been anything of particularly fine quality or desirability … until recently.

A Brief History of Emerald from Hiddenite, North Carolina
In the late 19th century, Thomas Edison sent professor William Hidden and George Frederick Kunz (the 19th-century gemologist-author who was curator of the gem collection at New York’s American Museum of Natural History and chief gemologist for Tiffany & Co.) to the area to seek platinum for light bulb filaments. They didn’t find platinum, but Hidden did discover a mineral that eventually became known as “hiddenite,” which, along with the town itself, was named in his honor. Together Kunz and Hidden noted sixty-three different gems and minerals, referring to the fault line running through this area as “the most complex geological zone in the world.”
            Over the years, Hiddenite attracted several mining companies and thousands of rock hounds, yet no one found anything exceptional, nor did the area appear to be commercially viable as a source for emerald. The most significant emerald unearthed in Hiddenite was a 13+ carat-faceted-emerald purchased by Tiffany & Co. in the early 1970s, and named “The Carolina Emerald.” Its unveiling generated extensive publicity and excitement and was described as one of the rarest gems ever discovered in America. Its estimated value at that time was $200,000.
            Although several nice emeralds have been found over the years, most are too pale or opaque to have jewelry value. This changed in the fall of 1998 when James (Jamie) Hill, president and CEO of North American Emerald Mines, the company created by Hill to market and promote Hiddenite emerald, announced the discovery of a vein yielding large, gem-quality emeralds.

The First Gemological Evaluation of the New Find
Already knowing the history of emerald in North Carolina, it was hard to believe there could be gem-quality emeralds there, but I accepted the invitation from Jamie Hill to visit the site anyway and to examine the emeralds he had unearthed. My skepticism was quickly replaced by serious interest, and the first trip became the first of many trips to Hiddenite to witness the progress of the mining operation and acquire material for in-depth gemological evaluation.
            Hill’s family owns a 94-acre parcel of land on which mining activity is currently occurring. Initially, when surveying the property, all that could be seen was a lot of red clay, trees and hilly terrain with some rock outcroppings. Hill’s preliminary mining operation consisted of three men using shovels, picks, and some second-hand heavy equipment capable of removing surface soil and rock in order to expose a particular type of vein that Hill identified as being associated with the emerald occurrences. Hill sought “veins” containing a combination of limonite (a powdery yellow substance, from decomposed pyrite), pyrite, mica, and quartz. He was looking for emerald-bearing “pockets” within the vein. Hill explained that every emerald he’d found at that time had been the result of following veins that contained this particular combination of minerals. Following the vein, he would hit a pocket, reach into it and feel around for crystals, then bring out whatever he felt.
Not all pockets he opened contained emerald, but all of the emerald he recovered had been found in at least one of the pockets, alongside small hiddenite crystals and perfectly formed, 6-sided quartz crystals—smoky and colorless. Area geologists told Hill that the crystals appeared to be the result of hydrothermal formation.
            That first major discovery in the fall of 1998 included two of the largest and finest crystals ever unearthed in North Carolina—a 1,000-carat crystal he named  “The Jolly Green Giant,” and a 70+-carat crystal of excellent color and brightness. The 1,000-carat crystal had fine color and was a fine crystal specimen, but it was too heavily included to facet. The 70-carat emerald crystal was a different matter; it yielded two notable gems—a 7.85 carat oval named “The Carolina Prince,” and an 18.88-carat pear-shape named “The Carolina Queen.” The Prince sold for $500,000 to a North Carolina collector who wanted a piece of “North Carolina history in the making.”
            The Carolina Queen is currently regarded as the rarest emerald ever discovered in America, and is the largest and finest ever recorded. In size, overall quality, and in its rich, deep green color, the 18.88-carat emerald far surpassed any faceted emerald discovered in America up to that time, including Tiffany’s “Carolina Emerald,” which is much paler in color, lacks the intense brightness of the Queen, and is more included. The report issued by American Gemological Laboratories in New York City described this historical gem as “the largest, finest and most significant emerald ever found in America.” In addition to the two large crystals, Hill also extracted other crystals, the total yield at that time being over 3,000 carats.

State of North Carolina Suspends Mining Activity in 1999
Hill’s emerald discovery generated extensive media coverage and national publicity. This, along with Hill’s announcement of his intention to expand mining activity, resulted in an intervention by the state of North Carolina, which changed the status of the site from “prospecting” to “commercial mining.” The change in status meant that Hill would be required to comply with state ecological requirements and others in order to obtain the commercial mining permits necessary to continue mining his site. Work was suspended from 1999 until 2002.

A New Discovery in January 2002
The state requirements were time consuming and expensive, but resulted in another important discovery that would enable Hill to mine much more efficiently. In order to comply with state requirements, Hill and his team had to move many tons of red clay. In doing so, they uncovered a massive rock dome that no one knew existed below the clay. It was daunting—the first images that came to mind upon seeing it were the early images of the surface of the moon. It revealed geological “folds” of rock going in every direction, and “veins” criss-crossing its surface everywhere. It was certainly easy to understand what Hidden and Kunz meant by “complex geology.”
            Hill and his team didn’t know where to start, but he investigated the possibility of using subterranean radar imaging in a small area of the dome to see if it would reveal any of the “pockets” he sought. Hill had actually looked into this at an earlier stage, but had abandoned the idea when he learned the radar could not penetrate red clay. But now, having removed the red clay, the exposed rock dome was a different story. A company specializing in subterranean radar imaging was commissioned to probe a small section of the rock dome, approximately one-fourth of an acre.
            On January 11, subterranean imaging commenced and revealed a number of pockets. Hill and his team proceeded to open one of the largest first—a pocket about four-by-twelve-feet wide—and were stunned to find two very large, rich, deep green emerald crystals at the very entrance to the pocket. The 70+-carat emerald rough which Hill had unearthed in 1998 no longer held the record as the most important emerald ever found in America; the new title was now claimed by the “twin crystals.”
            The two emerald crystals found at the opening of this new pocket remain “in situ,” exactly as they were uncovered. The entire “pocket” was excavated from the hard rock dome by removing a huge block from the site, retaining the emerald crystals within the matrix, along with two large, perfectly terminated quartz crystals that crystallized alongside each emerald. It is impossible to know their exact weight, but the exposed area of the largest appears to be about 100 carats, and the smallest about 40 carats. However, depending upon how far they penetrate into the rock wall, they could be larger. In the days immediately following, another twelve large emerald crystals were extracted from the surrounding area.

Gemological Properties of Emerald from the Hill Site in Hiddenite, NC
These initial finds generated tremendous excitement within the geological and gemological communities. The Smithsonian sent geologist Michael Weiss to study the site and the head gemologist at American Gemological Laboratories, C. R. Beesley, conducted extensive research at the site, studying large numbers of emerald crystals from this locale, as well as all of the gems from the site that had been cut and polished to date. Several criteria have been identified for positive confirmation of Hiddenite, NC, origin, and other characteristics may be identified as analysis continues.

Unique Gemological Characteristics of Emerald from the “James Hill” Site, Hiddenite, NC
What is most notable about these recently uncovered emeralds is not size but overall quality, which is the finest ever seen from an American emerald site. It is also important to note that “origin” of emerald from this locale can be definitively established from gemological characteristics. Here is a summary of identifying characteristics that have been noted to date, and are based on extensive research conducted by American Gemological Laboratories and Gemcore (New York City), under the supervision of C. R. Beesley.
            Color. The color is particularly noteworthy—a deep, rich green comparable to fine emerald from Colombia. The color results from the presence of chromium. Reactions through the Chelsea filter range from moderate to a very strong red, depending upon the depth and evenness of the color. It should be noted, however, that in some crystals the color has been found to occur in zones. In cases where the color-zone is very narrow or confined to a small portion of the stone, no noticeable reddish reaction may be detected through the Chelsea filter, regardless of the face-up color. In the finest material, the reaction through the Chelsea filter is a very strong red, comparable to the reaction seen in material from Colombia.          
Gemologists from around the world have been impressed by the intense green color seen in the finest of the emeralds to have come from this source. Perhaps most impressive was a faceted 1.76-carat cushion-shape, which exhibited a superb green color and startling brightness. It is a gem comparable in color to Colombia’s finest material.
            Refractive Index. The refractive index of this new material is consistently high, and contributes to the unusual brightness seen regularly in the cut and polished material. The RI ranges from 1.579 on the low end to1.589 at the high end, higher than Colombian material.
            Spectral Characteristics. Spectral characteristics are distinctive and provide an immediate key to origin of Hiddenite emerald, and to distinguishing it from other chromium-type emerald, including those from Colombia. However, its unique spectral characteristics may not be seen if observing the stone with a hand-held spectroscope model.
            Fluorescence. All the material examined to date exhibits a unique fluorescence—a faint yellowish or bluish-chalky fluorescence under shortwave. Such fluorescence has not been observed in emeralds from any other location. To detect the fluorescence, you must examine the stone in a darkened space, on a flat, black surface (such as a black velvet pad), holding a UV lamp directly up to the stone.
            Distinctive Inclusions. Inclusions of rutile needles provide definitive, positive confirmation of Hiddenite, NC, origin—inclusions of rutile needles have not been found in emerald from any other locality. Rutile inclusions may not be present, however, and some of the inclusions seen in this material are consistent with other localities. No three-phase inclusions have been seen in the material examined to date, but as more material is examined, other unusual inclusions or combinations may provide additional keys to Hiddenite origin.

Antoinette Matlins, PG, is a highly respected author and educator. Her latest books include Colored Gemstones, 3rd Edition: The Antoinette Matlins Buying Guide and Jewelry & Gems, 7th Edition: The Buying Guide (GemStone Press, Woodstock, VT, www.gemstonepress.com).