What use is alexandrite

The name of this stone goes back to the Russian Tsar Alexander II (1818-1881), one of whose favorite stones he was.
It is particularly interesting because it appears beautifully green in daylight and purple in artificial light. That is why it is said of it that it is an emerald by day and like an amethyst in the evening. This interesting phenomenon is caused by the absorption of some colors in the light spectrum. Alexandrite cat eyes are also known.

Alexandrite originates tertiary in chromium-containing mica schists. It forms during metamorphosis in the contact zone between two rocks, one of which supplies the minerals aluminum and beryllium, the other the necessary chromium.

Due to the rarity of these conditions, alexandrite also remains a rare mineral.

Beautiful light yellow, completely transparent crystals can be found e.g. at Lake Alaotra in Madagascar and very dark alexandrite crystals with a size of up to 2 cm in Zimbabwe. The most famous European site is in Marsíkov near Sobotín in Moravia.

The largest and most beautiful group of alexandrite crystals was found in the Urals. It is a druse with 22 crystals and a weight of 5 kg

Alexandrite forms thick-tabular rhombic crystals and interpenetrating triplets, the crystals of which intersect exactly at an angle of 60 °. Single crystals and triplets have always grown into the mica slate.

Since alexandrite is an expensive gemstone, there are quite a few fakes on the market. Above all, cut stones are often imitated by synthetic corundum (sapphire), synthetic spinel or doublets made of glass and garnet. Synthetic alexandrite itself is also on the market. In all cases, the differentiation is only possible through mineralogical-gemological investigations.

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