Everything you need to know about Alexandrite Gemstone

The gem alexandrite, nicknamed "emerald by day and ruby by night" for its striking reversible colouration from green to red depending on the illumination source, is widely regarded as one of the most remarkable stones in the gem collection.

Alexandrite Gemstone in finger


Even though it is the modern June birthstone, few people have seen a genuine alexandrite due to its extreme rarity and high price. Therefore, this chrysoberyl variety is particularly well-suited for use as a gemstone in jewellery.


The chrysoberyl variety known as Alexandrite is rare due to its chameleon-like properties. However, two factors contribute significantly to the price of an alexandrite. To begin, a higher value is assigned to colours closer to pure green and red— likewise, the more noticeable the hue shift, the greater the value. 

Colour change in Alexandrites can range from entirely opaque to nearly transparent (5%). As a result, the most desirable gems would completely transform from green to red. The value of blue greens and purple- or brown-reds is low.

Alexandrite Gemstone in day and night light


It appears green in natural or fluorescent light but transforms to a brownish or purplish red in incandescent lighting. This is due to the mineral's intricate absorption mechanism.

The striking colour change of Alexandrite has led to the idiom "emerald by day, ruby by night" being applied to the gemstone. Although this is not the only gem whose colour shifts when exposed to different lighting, the alexandrite effect has come to be used to describe the phenomenon in general. Hence, its 70.94 carats aren't the only thing that makes this rough Alexandrite beautiful.

Additionally, Alexandrite is a highly pleochroic gem, which displays different colours depending on your viewing angle. Green, orange, and purple-red are the three pleochroic colours it typically shows. However, the gem's unusual light-absorbing properties, rather than pleochroism, are responsible for the dramatic colour change.

Alexandrite is one of the most expensive chrysoberyls due to its scarcity, especially in larger sizes. As with cultured pearl and moonstone, it is also a June birthstone.


Birthstone Lustre Cleavage
June Vitreous. Distinct to poor, 1 direction.
Pleochroism Colours Absorption Spectrum
Dark red/orangish yellow/green. (Myanmar gems anomalous: purple/grass-green/bluish green). Colour shifts from incident light; when exposed to natural light, it appears green, blue-green, or pale; and when illuminated by artificial light, it seems mauve, violet to red, purplish. Narrow doublet at 6805/6875, with weak, narrow lines at 6650, 6550, and 6490 and broad band at 6400-5550. Total absorption below 4700.
Phenomena Occurrence Luminescence
Colour change, chatoyancy (very rare). They are found as stream pebbles and detrital grains, as well as in pegmatites, gneiss, mica schist, and dolomitic marbles. Present
Special Care Instructions Crystallography Luminescence Type
None Orthorhombic Fluorescent, UV-Long, UV-Short
Formula Optic Sign Transparency
BeAl2O4 + Cr Biaxial +, Biaxial - Opaque to transparent.
Refractive Index Optics Etymology
1.745–1.759 Biaxial (+), may also be (–), 2V = 70°. Named after Czar Alexander II of Russia.
Dispersion Birefringence Hardness
0.015 0.009–0.010 8.5
Luminescence Variety of/Mineral Specific Gravity
Weak red in SW and LW. Chrysoberyl 3.68–3.80
Heat Sensitivity Fracture Wearability
Yes. Weak conchoidal to uneven. Excellent



It was in 1830 that geologists discovered substantial alexandrite reserves in the Ural Mountains of Russia. A well-known mineralogist named Nils Gustaf Nordenskiöld was the first to recognise the novelty of this green gemstone's shifting hue. It was in 1834 that Count Lev Alekseevich Perovskii gave the stone its current name in honour of the soon-to-be Czar of Russia, Alexander II.

Those first alexandrites were stunning specimens of the gemstone, bursting with a rainbow of colours and showing off an incredible range of tones. The future King Alexander II was honoured with the naming of this precious stone. Its attention-getting red and green hues evoked the imperial Russian national military colours, and the country took notice.

Alexandrite Gemstone original form uncut stone


This diamond's beauty, fame, and rarity have captivated the public's mind. Moreover, the 1950s saw the addition of Alexandrite as a birthstone, replacing the traditional pearl as the birthstone for June.

The spectacular Ural Mountain deposits in Russia were once the primary source of Alexandrite, but these days it is usually obtained primarily from Sri Lanka, East Africa, and Brazil. 

While some high-quality stones are in the newer deposits, many have less precise colour transitions and darker hues than the Russian alexandrites of the nineteenth century.

However, there are still antique pieces of jewellery set with alexandrites from the renowned Ural Mountains. Yet, they continue to set the standard for excellence for this fantastic gemstone.

Multiple Sizes of Alexandrites

The Smithsonian Institution is home to the largest faceted Alexandrite, a 65.7-ct green/red colour-changing stone from Sri Lanka. About 30 carats are enormous Russian jewels available. The bulk of alexandrites, however, are under one carat in weight. However, five-carat stones are exceptional, especially those with good colour change.

Alexandrite stone


Other sizable alexandrites include the following:

  • The B.M.NH (London) has 43-carat and 27.50-carat diamonds, respectively (Sri Lanka).
  • The Russian Academy of Sciences Crystal Collection: a 6-3 cm crystal triple (Urals).
  • The Fersman Museum in Moscow, Russia, houses a 25 cm by 15 cm crystal group that features crystals as large as 6 cm by 3 cm (Urals).
  • Stones up to 50 carats have been reported from private collections.

Care of Alexandrites

Alexandrite is a very tough gemstone with a hardness of 8.5, making it ideal for use in any type of jewellery. But you should be careful when you cut the stone into facets. Still, knocks and high temperatures can damage Alexandrite.

Care of Alexandrite stone


These precious stones need no extra maintenance. According to the system's guidelines, you can clean them mechanically. You can also use a brush and warm soapy water to clean them.

Frequently Asked Questions

1. How much is a real alexandrite stone worth?

In terms of market value, Alexandrite ranks among the very highest. Alexandrite with a GIA certification, can cost up to $15,000 per carat. Depending on its rarity and quality, Alexandrite can sell for as much as $70,000 per carat.

2. How much is a 1-carat alexandrite worth?

Alexandrite's worth is always affected by its size. You'll see that this is reflected in the Price List that follows. Natural gems of exceptional quality can fetch up to AU$21,429 per carat for stones up to one carat in size. Diamonds larger than one-carat cost between AU$71,429 and AU$100,000 each.

3. What is so special about Alexandrite?

In different lighting conditions, the amazing Alexandrite gemstone takes on a green or red hue. The "alexandrite effect" is one name for this phenomenon of changing colour. Alexandrite is one of the most desirable gemstones because of its rarity and ability to transform into nearly any other colour.

4. Is Alexandrite really rare?

Natural Alexandrite is one of the most demanded jewels in the world, but it isn't easy to come across. It is easily identifiable by the colour shift that occurs, going from a greenish blue in natural light to a reddish purple in artificial illumination.

Even while Alexandrite has become more readily available thanks to discoveries in Brazil and other places, it is still far more scarce than other gemstones, such as diamonds.