A dramatic colour change can be observed when it is lit by natural daylight and then by an artificial light source with an Alexandrite. While he is initially in a bluish green robe, he is transformed into the sequence and takes a dramatic-looking, reddish-purple hue. The technical term for this phenomenon is changing; It is also often referred to as Alexandrite effect, because this is the most popular and most famous gem that has a so significant color change.
The first Alexandrite in Russian Tokovaya mines in the Ural mountains have been found in the 1830s and later was named after the gemstone to the honour of the Russian Tsar Alexander II (1818-1881). As he reflected exactly the former colours of the army with his green and red, he was known also as Russian national precious stone.
Alexandrite and its certification by the reputable organisations GIA, AGL and GRS
In an Alexandrite the colour with the traversing is the most important criterion for determining the quality. The AGL (American Gemological Laboratories) on their type therefore prestige gemstone report for Alexandrite in percentage points to how strong the traversing is pronounced and is also assessed, as nice and evenly this process runs. 100% would correspond to a complete color – it virtually never happens; very high quality precious stones move in the range of 85 to 90%. In addition, a certificate of the AGL provides information to Carat number, cut form, place of origin, and any artificial treatments.
Since there is no internationally accepted guidelines for assessing for coloured gemstones, a certificate of the GIA is different (Gemological Institute of America) from one of the AGL. So are located in a GIA Alexandrite report no information on the intensity of the optical effects, but only the standard details of the gemstone.
A Gemstone Report of the GRS (Gemresearch Swisslab) for an Alexandrite commented on the color change, where for example “prominent color change from olive green to salmon – red” to read.
The stunning traversing of an Alexandrite gem – switching between diverse shades of green and Red
There are Alexandrite depending on the light source – in a broad range of different shades of green or red. Very often a bluish green is visible in daylight, artificial light and by candle light, however, a purple. In a variety of shades is still possible; There are gems that orange, reddish purple, or grey violet colour and the mysterious traversing each stone has a very own look. There are hardly two Alexandrite gems that offset each other.
The so decisive for the Alexandrite optical phenomenon created by the specific absorption spectrum of the gemstone, which is permeable only for green and red rays of light, as well as the different composition of artificial and natural light.
As a whole is that a gem even more valuable is, more pronounced the color change and the individual colors are ever more lively and attractive. An Alexandrite has brownish or gray undertones, however, so this affects negatively on its value.
Ideal would be there, if the gem of both day and night has an intense colour that is neither too bright nor too dark. There are only a few Alexandrite that look beautiful in any light source. It is considered unfortunate, if in a lighting situation both the Green and the Red can be seen, however, this is not a rare phenomenon.
Apart from the characteristic traversing under different light sources, a so-called Pleichroism can be observed when an Alexandrite. That is a technical term for this, if in a gemstone colour depends on the respective point of view of the observer. Under natural lighting, visible three shades are as a yellow-orange, an emerald green and deep red in artificial light a yellowish red, a dark red and a dark green.
Alexandrite and his original place of origin – the Russian Tokovaya mines
For the first time, Alexandrite have been found together with emeralds in the Tokovaya mines located near the Russian city of Ekaterinburg in the Urals. Largely due to their excellent quality, characterized these copies, because in them the colour change is particularly well apparent. Meanwhile, the local deposits are exploited and new localities have gained in importance. So, it was discovered in 1987 in Hematita in the Brazilian State of Minas Gerais deposits. The there gained gems that have usually a bluish green hue in the light of day, meet a high quality standard.
The traversing an Alexandrite originating from Sri Lanka and Tanzania, is usually less pronounced. Other places at which, the gemstone was found, located in India, Madagascar, Tanzania and South Africa.
The relevance of the degree of purity of an Alexandrite
Only a very small number of Alexandrite gemstones is transparent and completely translucent. Inclusions are the rule and give its own character every single gem.
Especially for larger Alexandriten, these impurities but can have a negative impact on the Crystal structure, which is more prone to tears. There are only a tiny number of pure gems that have a size of about one carat. The purity is rated on a five-part scale of Eyeclean up to Severely Included .
There are also imitations on the market and this man-made gemstones have a very high degree of purity. In its value, but they are not with a genuine Alexandrite to compare and they must be marked for sale in any case as spurious.
Alexandrite in the various fancy cuts
Due to the high value and the great rarity of the gemstone, is to maintain as much as possible of the original weight and to make smaller cuts in the symmetry in purchase sure grinding of an Alexandrite in particular. However, the gem in a carefully and well proportioned cut form has a nicer effect.
The oval cut works well, because it can keep a maximum number of carats – with a round brilliant cut the loss would be larger lot. Meanwhile, there are the Alexandrite in the variety of Fancy Cuts like the Emerald cut, the princess cut, cushion cut, or the drop cut.
The Alexandrite cat’s eye – bleak gems with beautiful light figures
In very rare cases may be at an Alexandrite to a cat’s eye effect, which on the slightly clouded stone surface a lighter slot-like shimmer of light to see, which is similar to the eye of a cat. The greatest demand is for the darker colored gems, because for them the most effect for days.
Price examples for the Alexandrite
The Alexandrite is one of the most expensive gemstones in the world and the prices of high-quality copies are similar to those of precious rubies or emeralds.
The cost of a 0,6-karätigen Alexandrite princess cut with very good degree of purity, which has a colour change from a lively, dark bluish green to a vibrant purple pink, to around 3,000 euros.
A one-carat stone equivalent quality Emerald cut approximately 7,500 euros.
They can expect approximately 11,200 euros at a 1.8 Carat oval-cut, which oscillates between a vibrant medium bluish-green and a vibrant purple pink.
Gems of exceptional size
The largest ever found Alexandrite in raw form was found in Sri Lanka and had a weight of 1.876 carats. In the meantime he was divided into several small gems long since.
In ground form, the record is held by a 66-karätigen Alexandrite, the Smithsonian Institution is kept in Washington.