Alexandrite is a rare chrysoberyl gemstone that changes colour in response to a change in light source. The effect of daylight gives the Alexandrite a lush green emerald colour by day, but changes to a red ruby like colour by night. 

Current market information from Paul Brereton, gemologist: The finest material comes from the Ural mountains in Russia although this source is now nearly exhausted. Most gemstones are currently being sourced from Sri Lanka and Brazil.  Most of these stones lack the strong colour change seen in the Ural material.  

The price of alexanderite is determined by three things:

1.  How pure green the colour is in daylight. This means the more green, the more expensive. As more modifying colours come in, such as the color brown, the less expensive the stone.

2. How pure red the colour is in lamplight. This means the more red, the more expensive. As more modifying colours come in, such as the color brown, the less expensive the stone.

3. How strong is the colour change? The more defined the colour change the more expensive the stone. When the stone has only a marginal change in colour this drastically reduces the price of the gem.

Please be aware that stones over one carat that have true-red, true-green colours and a strong colour change trade for a large premium - starting at circa €10,000.

There are also synthetic versions of the stone available internationally which are inexpensive but Brereton's only deal in natural gemstones.

Alexandrite was named after Czar Alexander II. 

Sources: Russia, Sri Lanka, East Africa, Brazil. 

Hardness: 8.5 on Mohs scale. 

Toughness: Excellent. 

Alexandrite is an alternative birthstone for June. 

To view our collection of Alexanderite jewellery please contact us at webenquiries@brereton.ie.