Gemstone Guide: Gems to invest in and what to buy
If you’re ever confused about the provenance of time-honoured favourites and newly popular gems, this general guide can help.
In today’s kaleidoscopic gemstone and jewellery industry, the discovery of new mines mean fine emeralds are no longer just Colombian; impeccable rubies are not only Burmese; and top-grade sapphires do not hail solely from Sri Lanka (Ceylon). A cursory glance at the fine jewellery collections by international brands would already throw up various countries of origin for one gemstone alone. Since the industry does not always adhere to the same guidelines, some terms used to describe gemstones may range from colours to localities to mineral varieties.
Apart from old versus new, there are also antique or heirloom gemstones whose origins are unknown or hark back to ancient lands whose boundaries or territories simply do not exist anymore. You’d imagine that examining large, fine gemstones put out by the world’s top maisons would clear the air up, but the fact that these jewellers only select the best specimens means it is difficult for the layman to easily differentiate gemstones of different regions or sources. Nevertheless, being armed with some basic knowledge could help us make better and wiser buying decisions, if not sound more intelligent or interesting over the dinner table.
Opals are commonly found throughout the world, but precious and gem-quality varieties only come from very specific localities. Australian’s famous mines in the Outback produce over 90 per cent of the world’s fine opals of all colours, with Coober Pedy being the location where the world’s largest and most valuable opal was found, and Lightning Ridge being the most prestigious and frequently featured in high jewellery collections for its rare and stunning black opals.
Ethiopia had traditionally produced poor-quality opals until as recently as 2008, when a fine gem-quality deposit was found in the Wollo province. Called Welo opals, these specimens are mostly white and display very vivid play-of-colour.
An up-and-coming type of opal adored by jewellers is the fire opal, the best examples of which have a transparent to translucent bright, fiery orange colour. The only country where significant deposits are found is Mexico, which has been mining it from the highlands since 1835 and eventually adopted it as the national gemstone.
Due to their extreme scarcity, sheer beauty, as well as huge demand, the finest rubies from Burma (or Myanmar) are dearer than the best sapphires and emeralds, and even diamonds. Burmese rubies also command a premium over other rubies because of their special qualities. They have a glorious legacy as royal gems that pre-date recorded history; boast a pure, intense red called Pigeon’s Blood that holds its colour under all lighting conditions; and display a super-charged fluorescence under ultraviolet light (and also sunlight) due to their high chromium content.
While there are many ruby mines in Burma, the prized variety hail from Mogok in Upper Burma and possess very fine silk inclusions that maximise their brilliance. Unfortunately, the old mines have been all but nearly depleted, and the new Burmese specimens produced typically do not match up to their predecessors, although the name “Burmese” would already command a premium in prices.
Apart from Burma, historic rubies came from mines in Sri Lanka, Thailand, and Cambodia that have all been exhausted.
Since the 1960s, East Africa has been the newest source for fine rubies, with Mozambique, Madagascar, and Tanzania being the main suppliers. Because the African specimens are iron-rich, they tend to be darker in red or have a purple undertone, while some display a slightly lighter pinkish red.
Since the 1980s, mines in the north of Vietnam have also produced some rubies and pink sapphires that aren’t as fine and clean as those of Mogok’s. Meanwhile, Greenland is touted to become the next big locality for high-quality rubies and pink sapphires after mining operations began last year.
Colombia is the global leader and brand for emeralds, being responsible for the lion’s share of the precious stone’s production in the world since antiquity. Due to the prestige of heritage and legacy, Colombian emeralds still command the highest price per carat.
Another South American country that also produces emeralds is Brazil, which only started doling out top-grade stones in the 1980s after many decades of mining affordable mid-range specimens. Zambia, located in the landlocked southern part of the African continent, is the newest kid on the block for emeralds. It is also rich in other gemstones such as tourmalines and aquamarines, and has attained the status of the second largest producer of fine emeralds in the world in recent decades.
The trace elements colouring the emeralds are chromium for Colombian specimens; vanadium for Brazilian; and iron for Zambian. The green of Zambian stones tend to be more saturated than the Colombians, and could even appear bluish due to the presence of iron. However, the famous Chivor old mines also produced emeralds with a deep, blue-tinged green.
The Brazilian stones, meanwhile, typically display a slight brown or grey cast. The type of inclusions present in emeralds also varies by their origin. Colombian emeralds are likely to have more inclusions than Brazilian and Zambian emeralds.
Very recently, the remote emerald mines of Panjshir Valley in the Hindu Kush mountains of Afghanistan are coming under the spotlight as a potential source for emeralds of excellent colour and clarity, rivalling the best Colombians and Zambians.
Antique Russian emeralds are prized for their colour and lucidity, and were mined from the Urals in the 1800s up until the 1990s. However, they are extremely rare today due to sporadic production and eventual mine closure.
While the most legendary blue sapphires originated from Kashmir, the northern Indian region has stopped production for so long that most of the existing specimens you see today are over 100 years old, and so exceedingly rare they usually take pride of place in a museum or auctions. These sapphires are where the term “cornflower blue” came from, displaying a desirable striking and vibrant hue similar to that of cornflowers. Due to a certain type of rutile inclusions, Kashmir sapphires also possess a beautiful velvety quality.
Next on the prestige scale are Mogok sapphires, which are also highly limited due to the depletion of the Burmese mines. They are typically darker blue and more transparent than the Kashmir stones, with the best ones displaying a deep, rich midnight blue.
Sri Lanka (Ceylon), meanwhile, is also reputable for astounding sapphires of not just blue, but every known sapphire colour. Hues for the blue sapphire range from a pale, almost cornflower blue to the highly regarded intense royal velvet blue. Among its famous stones include the largest blue star sapphire in the world, called the Star of Adam, which was found in 2013 and weighs some 1404.49 carats; as well as Princess Diana’s 12-carat blue sapphire engagement ring, which now belongs to Kate Middleton.
And in addition to other lust-worthy sapphire colours such as brilliant pinks and glowing yellows, Sri Lanka is also well known for its highly coveted Padparadscha sapphires, which are an ethereal, delicate pink-orange akin to the shade of the lotus flower.
Frequently featured by Tiffany & Co. are Montana blue sapphires, which were discovered in Montana state in 1865 by a gold miner working along the Missouri River. The blues are typically not large, and lighter in hue than the Sri Lankans and Burmese. Other colours, including orange, yellow, green, pink, and colourless, have also been found in Montana although the mining there is still small-scale.
Other countries where fine sapphires are found include Vietnam, Tanzania, Thailand, Cambodia, Madagascar, Tanzania, and Australia.
Of the many terms used to describe tourmalines, the colour prefix is usually the most common, since the gemstone is one of the most colourful on Earth. The shades adored by high jewellers are blue, green, and pink, but even tourmalines of the same colour are not equal.
Among blue and green tourmalines, an expensive and valuable subset is the neon greenish-blue Paraiba tourmaline, which was first discovered in the Brazilian state of Paraiba in 1989. With its lively hue, electrifying “swimming pool” effect, and limited supply, the radiant Paraiba quickly became a darling in the industry. In 2001, similar stones of outstanding quality were discovered in Nigeria and Mozambique, which led to the term Paraiba-like, or simply Paraiba, being used for these African stones.
While debate rages over the use of the name Paraiba, some dealers and jewellers use other descriptive terms. For instance, Tiffany & Co. uses the prefix Cuprian Elbaite: cuprian meaning copper bearing, which is the element that imparts the greenish-blue to the tourmaline; while elbaite is tourmaline’s specie name. An even rarer blue tourmaline is the indicolite tourmaline, an iron-bearing elbaite variety that displays a purer light to dark saturated blue; while the elusive chrome tourmaline, coloured by chromium and vanadium, possesses an intensely saturated forest green.
There is also the superstar among pink tourmalines: the rare rubellite, named for its luscious, ruby-like hue. To be worthy of the name, a pink tourmaline has to display a saturated pink or crimson tone, and must hold its colour regardless of the light source. Sometimes, when tourmalines display two or more colour zones, such as green and pink, they are called watermelon tourmalines.
In general, apart from Brazil, Nigeria, and Mozambique, tourmalines are found in Afghanistan, Pakistan, Russia, Burma, Sri Lanka, the US, Madagascar, Namibia, and Tanzania.
This article was first published in WOW.