Australian Emerald

From Cleopatra to conquistadors, the lust for its rare, beautiful greens has made Emeralds one of the world’s most valuable gemstones. An antipodean twist on Beryl’s most prized variety, Australian Emerald hails from the Curlew Emerald Mine (Est 1976), a small deposit at a remote location in East Pilbara’s Shaw River District. In 2007 a small mine-to-market collective secured the exclusive mining rights to the Curlew Emerald Mine, and have been actively working the deposit since 2011. A truly ‘green’ gem, Australian Emerald is ethically and sustainably mined with exceptional value afforded by vertical-integration. Emeralds from the Curlew Mine are incredibly scarce, and not readily available in the jewelry marketplace.

Hardness 7.5 – 8
Refractive Index 1.565 – 1.602
Relative Density 2.67 – 2.78
Enhancement Filled (minor clarity enhancement with a colorless liquid polymer resin)

Beauty

Color is king for Emerald with four criteria determining beauty and value:

1. Color Purity
2. Transparency
3. Clarity
4. Brightness (signature brilliance, often described as glowing, satiny, silky, soft or warm).

Australian Emerald displays classic ‘emerald greens’, with a desirable medium to medium-light tone and saturation, and an attractive translucent to semi-transparent opacity, affording a beautifully delicate ‘green fire’ brightness.

As a GIA (Gemological Institute of America) Clarity Type III gemstone, Emerald’s visible inclusions, termed ‘jardin’ (French for ‘garden’), are a characteristic trait and totally acceptable. Emeralds usually grow slowly within metamorphic rocks (rocks that have undergone a physical change due to extreme heat or pressure), which limits their size. This violent environment, combined with chromium and vanadium trace elements, encourages the formations of inclusions. All things being equal, cleaner large Emeralds are worth more simply because of geological scarcity. Aside from assured provenance afforded by mine-to-market chain of custody, under 10X magnification these Emeralds display typical banded inclusions, indicative of their natural Australian origin.

Quality of cut is very important for Emeralds as a skilled lapidary can locate its inherent eye-visible inclusions in a way that minimizes their impact on beauty. Optimally cut, Australian Emerald displays an excellent shape, finish, outline, profile and proportions, affording maximum brightness and beauty.

The famous equidistant steps of the ‘emerald cut’ are designed to reduce cutting pressure, accentuate Emerald’s satiny brightness, and in the case of Colombian Emerald, maximize crystal yield. While this traditional cut is synonymous with Emerald, cushions, ovals and pears are also possible for Australian Emeralds.

Emerald’s name is derived from the Greek ‘smaragdos’, which means ‘green gem’, but as with Ruby and Sapphire for reds and blues, prior to scientific advances in the 18th century, the name was used for any green gemstone. For example, because Green Sapphire was sourced from the Far East it was once known as ‘Oriental Emerald’. The birthstone for May, Emerald is a member of the Beryl mineral family (from the ancient Greek ‘beryllos’, meaning blue-green stone), commonly known as the ‘mother of gemstones’ because of its highly regarded gem varieties. Pure Beryl is colorless and trace amounts of elements are responsible for producing Beryl’s wonderful colors. Apart from Emerald’s greens, other Beryl gemstones include Aquamarine blues, Golden Beryl yellows, Goshenite whites (colorless), Heliodor greenish-yellows, Morganite pinks, and Red Beryl reds. Emerald is colored by trace amounts of chromium, vanadium and iron, with their relative concentrations causing an extraordinarily beautiful range of pastel to intense deep greens with varying degrees of bluish, brownish, greyish, and yellowish tints. Some professionals and gemological laboratories split Green Beryl and Emerald based on their coloring agents, color purities, hues or tones. In her excellent book, ‘Ruby, Sapphire & Emerald Buying Guide’, Renée Newman states: “there is no agreed-upon criteria in the trade for distinguishing between Green Beryl and Emerald”. She favors keeping it simple for consumers, using ‘Emerald’ to refer “to all Beryl ranging from bluish green to yellowish green regardless of its tone, color purity or coloring agent”. While an ostensibly sensible approach, there is typically a strict tone description required for Emerald. If it is not medium or darker many do not consider the gem Emerald. Instead they classify it as ‘Green Beryl’. While this might seem reasonable for practical purposes, scientifically the variety is defined by its coloring agent. The American Gemological Laboratory New York (AGL) recognizes any Green Beryl colored by chromium and/or vanadium as Emerald regardless of the tone. Almost all Emeralds contain iron as a trace element, though the amount may change from one formation to another. A Beryl variety that owes its green color to iron is only is typically named Green Beryl.

Prized for thousands of years, Emeralds were reportedly first traded 4,000 years ago. Historically, Emerald was the mean green beauty machine of the ancient world; Mesopotamians, Egyptians, Greeks and Romans all coveted the ‘greenest of green’ gems. For early civilizations surrounding the Mediterranean, Egypt is the place where Emerald’s story begins. Perhaps mined as early as 3500 BC, Egypt’s Emerald mines were located in Egypt’s eastern desert region and were rediscovered in 1816 by Frédéric Cailliaud, a French mineralogist and explorer. Even Greek miners braved heat, scorpions and snakes to unearth Emeralds there for Alexander the Great. This isn’t to say there weren’t other Emerald sources; the Habachtal region in the Austrian state of Salzburg might have yielded a few Emeralds, and Roman earrings featuring Emeralds from the Mingora mine in Pakistan’s Swat Valley have been discovered. There is also a legend that the Scythian Emeralds mentioned by Pliny in his Historia Naturalis were actually from Russia’s Urals, but as far as supply is concerned, Egypt had a near monopoly. Cleopatra, last Pharaoh of Egypt, was big on Emeralds; she wore sumptuous Emerald jewelry, decorated ornamental objects with them, and presented dignitaries with Emeralds carved with her likeness. While it’s tempting to think they were her favorite simply because of their beauty, Cleopatra was shrewd, intelligent and politically savvy. She understood the importance of symbolism, glamor and prestige in power and politics. Emeralds were more than just pretty gems to the Egyptians; they were potent patriotic symbols of national pride and she knew this. When Cleopatra finally consolidated her power base in 47 BC, with a little help from her Roman boyfriend Caesar, she was quick to claim the country’s mineralogical riches as her own. Despite being discovered some 2,000 years before her birth, the Egyptian deposits will be forever known as ‘Cleopatra’s Emerald Mines’. Taken over by the Romans after her death, Egypt’s Emerald mines were worked until the 6th century AD.

Featured in myths and legends in diverse cultures around the globe, Hermes gifted Aphrodite an enormous Emerald in Greek mythology, while in Hebrew tradition Emerald was one of the four precious stones given to Solomon. Since Egyptian times, Emeralds have been linked to fertility, immortality, rejuvenation, and eternal spring, so it’s no surprise they are the birthstone for May. Pliny bestowed the benefits of Emeralds to refresh and sooth strained eyes and even today, we have ‘green rooms’ to relax presenters in TV studios and ‘hospital green’ to calm patients.

While Egypt’s Emeralds are long gone, since the 16th century and the exploits of the infamous conquistadors Hernando Cortés (who campaigned against the Aztecs from 1519) and Francisco Pizarro (who campaigned against the Incas from 1526), a Colombian pedigree has become synonymous with Emeralds of exceptional quality. Discovered in 1931, Zambia has the world’s second largest Emerald deposit and is also known for producing fine quality.

Rarity

Emerald sources include Afghanistan, Brazil, Colombia, Ethiopia, Pakistan, Russia (Ural Mountains), Zambia, and Zimbabwe. Measured in value, Colombia is the largest producer, following by Zambia, Brazil, Pakistan, Afghanistan, and Russia.

While Australia has over 30 Emerald mineral deposits located throughout New South Wales, Tasmania and Western Australia, gem-quality crystals are extremely rare. Australian Emeralds have been commercially mined at four main deposits: Emmaville in New South Wales; and Poona, Menzies and Pilbara in Western Australia. Australian Emerald is typically associated with granite pegmatites (coarsely crystalline igneous rocks), in metamorphosed rocks called schists, and occasionally with altered limestones, or embedded in Calcite or Quartz.

The New England area of New South Wales has yielded most of Australia’s gem-quality Beryl, including both Emerald and Aquamarine. The largest deposit is found near Emmaville, but others occur near Inverell, Dundee and Glen Innes. First mined in 1890 by the Emerald Proprietary Company, a relatively large quantity (over 53,000 carats) of pastel to bright green crystals were unearthed from this area over 20 years. Small-scale mining and prospecting continued to 1963 with little success. Emerald also occurs at Fielders Hill near Torrington, as strongly defined green zones in colorless Beryl crystals. When cut perpendicular to the c-axis, they yield a standard Emerald, but when cut parallel they produce uniquely striped gems. Commercial mining was attempted in the early 90s, but wasn’t viable.

Emeralds were discovered in Western Australia near Poona in 1912, with small-scale mining and prospecting sporadically occurring, including the notable Agha Khan Mine in the 40s. Underground mining began at Agha Khan in 1979, but ceased in 1980 due to mining difficulties and low-quality gems. Nearly all Western Australia Emerald mining has occurred at Poona, but Emerald has also been mined at Menzies (since 1974), as well as at Pilbara, the source of our Australian Emerald.

A small deposit in a remote location, the Curlew Emerald Mine is situated in East Pilbara’s Shaw River District, approximately 90 kilometers west of Marble Bar. The mine’s pegmatites are composed of Quartz-Albite with Emerald, Scheelite, Molybdenite, and fine-grained purple Fluorite. While its history up to 1976 is undocumented, local folklore suggests Emerald was discovered here in the 20s.

A group managed by Bill Moriarty, a mineral specimen miner from Kalgoorlie, worked the Curlew Emerald Mine from 1976 to 1981. Annual production was approximately 4.5 kilograms of facet grade Emerald, with an additional 40 kilograms of lower, largely artisan grade. Per year on average, only 20 extremely fine crystals, weighing 3 – 4 grams, were unearthed.

In 1981, Warren & Strang (Australia) Ltd. purchased the mine, both mapping the deposit and conducting sample mining. Sold again in 1985 to Elders Resources Ltd., the mine’s low yields and dilapidated equipment seemingly made it more viable for a single miner or small group. With no buyers interested, the mining license expired in 1989.

In 2007 a small mine-to-market collective secured the exclusive mining rights to the Curlew Emerald Mine, and have been actively working the deposit since 2011. Currently semi-mechanized, the Curlew Mine’s Emeralds are extracted directly from their host rock. Small pegmatites and dark mica schists within the Quartz veins are accessed via a series of diggings extending approximately 500 meters. The miner’s estimate only one percent of all Emeralds from the Curlew Mine are gem-quality, with approximately 80 percent weighing below one carat. Mining at the Curlew Emerald Mine is restricted to winter (June – August), when temperatures are around a palatable 20°C. While summers exceed 32°C almost daily, temperatures above a scorching 45°C are not unusual. A truly ‘green’ gem, Australian Emerald is ethically and sustainably mined with exceptional mine level value afforded by vertical-integration. Extremely important in today’s gem and jewelry industry, nothing is lost to unnecessary middlemen, and provenance is assured. Not surprisingly, Emeralds from the Curlew Mine are incredibly scarce, and not readily available in the jewelry marketplace.

Regardless of origin, at least 99 percent of all cut Emeralds are sold with some sort of clarity enhancement. As Emeralds are never found with naturally occurring oils or resins, all Emerald clarity enhancements are considered artificial processes which are universally accepted in the trade with proper disclosure.

There exists within the gem trade some mythical folklore that cedarwood oil is somehow superior to resins as it is natural, as opposed to synthetic. In reality, not only are resins far more stable than cedarwood oil, which is in fact heavily processed, they also offer superior clarity enhancement, positively impacting beauty and value. The gem trade’s primary concern is providing customers with natural Emeralds which feature superior long-term stability. It makes no sense to enhance a beautiful Emerald with less stable cedarwood oil just because it is considered a ‘natural’ product. Since resins provide far greater long-term durability, a benefit to jewelers and ultimately to consumers, they are the logical and most practical choice.

Not surprisingly, at least 95 percent of all Emeralds currently in the marketplace, regardless of origin, are resin enhanced. For further information on this important gem trade subject please see the International Gem Society online article, Emerald Enhancements: A Consumer and Trade Guide.

Durability & Care

Australian Emerald (Mohs’ Hardness: 7.5 – 8) is an excellent choice for everyday jewelry. Always store Australian Emerald carefully to avoid scuffs and scratches. Clean with gentle soap and lukewarm water, scrubbing behind the gem with a very soft toothbrush as necessary. After cleaning, pat dry with a soft towel or chamois cloth.

Map Location

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