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Alexandrite

"Look, here it is, the prophetic Russian stone! O crafty Siberian. It was always green as hope and only toward evening was it suffused with blood."
Nikolai Leskov, The Alexandrite, Mysterious Interpretation of a True Fact (1884)
 
Tsar Alexander II (1818-1881)

 

Tsar Alexander II (1818-1881)
The ‘gem of the tsars’, or simply, the ‘tsar stone’, Alexandrite is a gemstone forever linked to the ruler for whom it was named, Tsar Alexander II of Russia (1818-1881), the country he ruled and the twilight of Russian aristocracy.

Alexandrite is the ultimate gemstone of duality and for me, its twin colours symbolically embody the Russian character, shifting fortunes of hope and hardship. Writing just three years after the death of Tsar Alexander II, Nikolai Leskov cleverly tied together the fates of Russia, the Tsar and the gem that received his name, defining Alexandrite as a prophetic stone. One of the classic Russian writers of the 19th century, Nikolai is regarded by many Russians as, "the most Russian of all Russian writers". Coming to the throne, liberal-educated Alexander knew the path to take to help his people, but at the same time, I guess it’s good to be king. Assuming power at the tail end of a humiliating defeat in the Crimean War, Alex thought the time right to modernise. Hailed as ‘Tsar Liberator’, his industrial reforms, new judicial administrations and most importantly, ending serfdom, correspond to Alexandrite’s daylight greens or as Nikolai put it, "green as hope".

But by the end of Alexander’s rule, these very reforms had created a hotpot of revolutionary zeal which, true to his autocratic legacy, was ruthlessly suppressed. Native languages were banned and over 250,000 people were exiled to Siberia, an irony considering Alexandrite was discovered in the Ural Mountains. These woes came to a head in 1881, when it was third time lucky for the People’s Will, a radical revolutionary group that succeeded in assassinating the Tsar. In the end, Alexander’s rule, in semblance to Alexandrite’s night time reds, was quite literally, "suffused with blood". Even though the writing was on the wall, Alexandrite became a potent symbol of hope and nationalism for Russian tsarists after Alexander’s death, not only because of its name and alleged discovery on his birthday, but also because this extraordinary gem can echo the Imperial Russian Military colours of red and green. Three tsars later, the Bolsheviks took power and it was finally curtains for the Russian monarchy.
 
An Alexandrite & Diamond 18K Yellow Gold Ring in natural (candescent) and artificial (incandescent) light showing its characteristic colour change
 
An Alexandrite & Diamond 18K Yellow Gold Ring in natural (candescent) and artificial (incandescent) light showing its characteristic colour change
If you haven’t already guessed from the above or this section’s lead photograph, colour change defines Alexandrite. A member of the Chrysoberyl family, Alexandrite is its most coveted variety. Chrysoberyl was named by German geologist Abraham Gottlob Werner in 1790, using the Greek ‘chryso’ (golden) and ‘beryl’ (green gemstone). Chrysoberyl is a particularly brilliant gemstone especially noted for its cat’s eye variety (click here) and although rare, it also changes colour, resulting in Cat’s Eye Alexandrite (a favourite with aficionados because it packs a phenomenal double whammy). Most Chrysoberyl is coloured yellow due to iron trace elements but vanadium very rarely yields vivid green examples (click here), while Alexandrite is coloured by chromium. Chromium is the Midas element that gives Emeralds and some Rubies their signature hues.

So it’s clear. If Chrysoberyl doesn’t change colour, it isn’t Alexandrite. Sure, there are other colour change gems, and a few of these are covered in this section, but most of these display a colour shift (a colour change where the two colours are near each other on the colour wheel) rather than the dramatic colour jump of Alexandrite. Alexandrite is pleochroic (click here for more), or getting more technical, trichroic (three-coloured). This means each Alexandrite crystal has three colours, green, red and yellow, whose intensity changes when it is viewed from different angles, but confusingly, this has absolutely nothing to do with its colour change. While you can read more about how colour change works click here, its down to natural (candescent) and artificial (incandescent) light having different amounts of the spectral colours (blue, green, orange, red, violet and yellow) and the way chromium absorbs and reflects light. Chromium absorbs the yellow spectrum as white light passes through Alexandrite, leaving an even split of blue and green. Sunlight is pretty balanced, proportionally containing more of the green our eyes favour, so it appears green in candescent light, while incandescent light has more red, so its colour changes to red. Simplistically, the better the concentration and configuration of chromium in Alexandrite, the better the colour change.

You may be wondering if the famous Alexandrite description ‘Emerald by day’ and ‘Ruby by night’ is really accurate. In his book, ‘Precious Stones and Gems’ (1898), Edwin Streeter says, "It has been said that the Alexandrite is an Emerald by day and an Amethyst at night", and this is telling. In reality, Alexandrite is not dependent on the colours of the change. In candescent light, Alexandrite can appear blue-green, forest green, green, khaki, teal or yellowish-green, and combinations thereof, and brownish-red, orangey-red, red or reddish-purple, and combinations thereof, in incandescent light.

The single biggest value consideration of Alexandrite is its colour change. Any colour change gem is judged by the strength of its change, and how attractive and distinct its colours are in both candescent and incandescent light. Colour preference is subjective, so I am not going to dictate tastes, but the ‘ideal’ Alexandrite will display distinct medium toned intense colours in both light sources, with the pure daylight greens to night time reds valued highest. Alexandrite that displays a percentage colour change of less than 30 percent or visible greyish, yellowish or brownish tints will be priced accordingly. Nevertheless, Alexandrite with a pure change of 90 percent or more is an impossible rarity for a gem that many regard as the rarest of them all. Good-looking colours that dramatically change is the pinnacle for Alexandrite, but actually seeing it change colour is dependant on several factors, including the intensity and purity of the two light sources, your eyesight, pleochroism, time of day, and even the weather. Standing under kitchen fluorescents with a cigarette lighter is probably not the best viewing environment; please just use your common sense. This alludes to a potentially confusing aspect of assessing colour change, called ‘bleed’. This is when a colour change gem’s two colours are visible at the same time. As most of us live in places where mixed lighting is the norm, ‘bleed’ is common, especially for a light sensitive colour change gem like Zultanite. Alexandrites that genuinely show an excessive bleed, diminishing their colour change, will be priced accordingly.

Cat’s Eye Alexandrite
 
Cat’s Eye Alexandrite
Alexandrite is classed as a Type II gemstone (click here for more), meaning you’re probably going to encounter visible inclusions, particularly when over 1 carat. For most gems, I preach the old mantra, “as long as inclusions don’t effect your perception of beauty, they don’t matter”, but in the case of Alexandrite more inclusions often accentuate the colour change. Whether you select a cleaner Alexandrite with a lesser change or a more included Alexandrite with a better change is up to you, just be aware that colour change is the key value determinant. Because of its intrinsic scarcity, Alexandrite is rare and expensive in any size. Most of what’s available is a quarter to half a carat, with the two, three and five carat markers resulting in exceptional price increases due to their comparative rarity. A fine quality 10 carats plus Alexandrite is either off to a museum or the realm of wealthy private collectors. Again, because of its inherent scarcity, Alexandrite is typically cut to maximise yield, which can result in proportions, windows (click here), inclusions and other flaws you’d baulk at in any other gem. As long as the gem changes colour and doesn’t look frightfully ugly, this is simply the nature of the beast. In my experience, the most common shapes are cushions, octagons, ovals and rounds.

Often described as the rarest of gemstones, Alexandrite’s rarity is inarguably its biggest asset and, along with its colour change, the main reason for its enduring popularity and high price. A lot has been written about the original Russian Alexandrite deposit, with many conflicting tales about when it was unearthed, named and by whom. The Emerald deposit (Izumrudnye Kopi) on the Tokovaya river where Alexandrite would later be found was discovered by chance in 1830 and by 1833 the as yet unnamed Alexandrite was found. Although it was undoubtedly Finnish mineralogist Dr. Nils Gustaf Nordenskjöld who figured out what is was, suggesting the less politically savvy name of Diaphanite (from the Greek ‘di’, meaning two and either ‘aphanes’, meaning unseen or ‘phan’, meaning appearance), in 1834, Count Perovskii coined ‘Alexandrite’, presenting it to the future Tsar Alexander II on his 16th birthday. But if Dr. Nordenskjöld lost out this time, his time would come. Publishing the first scientific paper on Alexandrite in 1842, he later discovered and named one of the green Garnet queens, Demantoid.

Russia and Sri Lanka were the only known sources of Alexandrite for approximately 90 years, despite the fact that no significant Russian Alexandrite was recorded since the 1917 Russian revolution. With the fall of the Soviet Union, rumours of new mining circulated (circa 1995). In 2005, Coloured Stone magazine reported, "new activity in this area", and in October 2006, Tsar Emerald began renewed production of the old Malyshev mine that originally opened in 1833. While I’m not holding my breath, Russia is a vast land, so who knows what the future will bring. Even though I don’t put credence purely in pedigree, some will pay a premium for certified Russian Alexandrite, even if low quality, which makes absolutely no sense to me. While Brazil, Burma, Madagascar, Mozambique, Sri Lanka, Tanzania and Zimbabwe have all produced small quantities of marketable Alexandrite, India is currently the most significant producer. Discovered in Chhattisgarh in 1994 and in neighboring Andhra Pradesh in 1996, Indian Alexandrite production is limited, constituting a tiny amount of the regular Chrysoberyl pulled from the earth.

Without a doubt, Alexandrite is one of the rarest, interesting, phenomenal and collectable of all gemstones. Let’s face it, Alexandrite’s got it all; beauty, sporadic availability, exclusivity (due to its high price), a cool name, fascinating history, bewitching folklore, is a birthstone for June, and to top it off, it even changes colour!

Colour Change Garnet


Colour Change Garnet
While colour change gems have been popular since Alexandrite’s 19th-century discovery, Colour Change Garnets weren’t reported until the 70s and it took the discovery of ‘alexandrite-esque’ hues to really spark interest. Namely, deposits in Tanzania’s Umba Valley (1987), Bekily in southern Madagascar (late 90s) and most recently (January 2009), near the village of Kamtonga in Kenya’s Taita Taveta District. Although colour change has been reported in other Garnets, most are an extremely rare variety of Malaia Garnet (also Malaya Garnet, a Pyrope and Spessartite mixture named for the Swahili ‘malaia’, meaning ‘outcast’). Its most striking colour change is due to high amounts of vanadium, in contrast to the chromium that causes colour change in Alexandrite. Having said this, chromium, along with magnesium, manganese and iron, is responsible for the colour change in some varieties. While typically changing from bluish greens to reddish purples or khaki greens to orangey-reds, other varieties of Colour Change Garnet include shades of blue, brown and grey that change to reddish purplish pinks. Usually only available in small sizes like Alexandrite, fine Colour Change Garnets can be visually mistaken for the ‘tsar stone’. While Colour Change Garnet is too obscure for a clarity type classification, moderate inclusions may sometimes be visible.
 

Colour Change Sapphire

Colour Change Sapphire
Very attractive, rare and thus highly collectable, Colour Change Sapphires are not regularly available. Sapphires frequently display subtle colour changes (colour shift) from natural to artifical light, but when the change is dramatic you have a rare gem indeed! For example, a very large mixed Sapphire parcel I reviewed only yielded 24 Colour Change Sapphires (6x4mm), each weighing around 60 points (0.60 carats). While they come in a myriad of colour combinations, Colour Change Sapphires are typically segmented into two groups based on their change colours: ‘blue to purple’ (including bluish-purple to purplish-red, violet to red-violet and purple to red-violet) and ‘alexandrite-esque’ (green, greenish-brown or khaki to red or brownish-red). Other colour combinations include pink to red and pink to green. While their change colours vary depending on origin, Tanzania is currently the main producer of Colour Change Sapphires. Most ‘alexandrite-esque’ Colour Change Sapphires are sourced from Tanzania (Songea), while ‘blue to purple’ Colour Change Sapphires are also found in Tanzania (Tunduru) as well as Burma, Madagascar, Sri Lanka and other East African countries. Colour Change Sapphires are scarce, especially over 1 carat, and are therefore typically cut to maximise rough yield. While colour preferences are subjective, all colour change gems are valued based on the strength of their colour change and the distinctiveness and attractiveness of their colours. For tips on buying Fancy Sapphires (the collective name for all Sapphires that aren’t blue), please click here.

Zultanite

Zultanite
First collected and faceted by ‘rock hounds’ (mineral enthusiasts) in the late 70s, Zultanite is now mined commercially. A rare colour change variety of the mineral Diaspore coloured by manganese, Zultanite hails from a sole deposit, a remote mountainous area in Anatolia, Turkey. Much like Alexandrite, Zultanite’s name also has a royal connection, being named by Murat Akgun in honour of the 36 sultans who ruled the Ottoman Empire in Anatolia in the late 13th century. Noted for its attractive earthy hues, Zultanite’s colour change is not limited to two basic colours, exhibiting a range of greens, purplish-reds and yellows in different light sources. Zultanite changes from kiwi greens with canary flashes under sunny skies, to rich champagnes in traditional indoor lighting and raspberry hues in candlelight. With up to 98 percent of the crystal lost during lapidary, Zultanite’s very low yield is one of the reasons it is so rare, especially in sizes over 5 carats. The clarity standard for Zultanite is eye-clean (no visible inclusions when the gem is examined six inches from the naked eye). Similar to Alexandrite, Cat’s Eye Zultanite is also available. Zultanite is a personal favourite and I wrote its page on the ICA (International Coloured Gemstone Association) website: www.gemstone.org.

You probably read the opening paragraph thinking, "What does Gavin know about Russia to make such comments?" Well, my wife is Ukrainian and her mum Russian, so I’ve been fortunate to add a few old wives’ tales to my more conventional understanding of Alexandrite. Getting thoroughly into Russian culture and history, I find the prophetic connection between Alexandrite and the land of its birth intriguing. After the fall of Russian imperialism, I bet many saw a new age on the horizon as green as the hope mirrored in Alexandrite at the start of Alexander’s rule. But the horror of WW2, of which Russia bore the brunt, soon saw Alexandrite’s reds again linked with the colour of blood, becoming known as the ‘widow’s stone’. Intriguingly, the name didn’t dissuade interest in this gem, so much so that ‘fake’ Alexandrite was a mainstay of Soviet jewellery. This is doubly ironic considering Alexandrite will forever be the ‘imperial’ gem, but I guess this embodies the uniquely Russian ability to mix hope with hardship. My favourite Alexandrite folktale is that if you only wear one piece of Alexandrite you will be lonely. Ostensibly due to its two colours requiring a partner, herein lies the problem: Alexandrite is uniquely individual and notoriously difficult to match!
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