A Jeweller’s Guide to Alexandrite: Identification Tips and Jewellery Making Advice
Famed for its extraordinary colour-change phenomenon, alexandrite is a gemstone that seems to hold magic within. By daylight, it may appear green or bluish-green, but under incandescent light, it shifts to reddish or purplish tones. This remarkable duality has earned it a reputation as one of the most intriguing and valuable gems a jeweller can work with.
Here’s everything you need to know about identifying and designing with alexandrite.
Basic Identification Information
Name & Synonyms:
Alexandrite (variety of chrysoberyl)
Species:
Chrysoberyl
Colour Range:
Green to bluish-green or yellowish-green in daylight;
Red to purplish-red or orangy-red in incandescent light
Refractive Index:
1.740 – 1.759
Birefringence:
0.008 to 0.010
Optical Sign:
Biaxial + or Biaxial -
Pleochroism:
Strong and 3 colours
Red, Orange-yellow, Green
Specific Gravity:
3.71 to 3.75
Fluorescence:
Usually inert, but some stones may fluoresce red
Lustre:
Vitreous (glassy)
Clarity:
Type 2
Eye clean examples can be found, but it's common for alexandrite to have eye visible inclusions
Gems Often Mistaken for Alexandrite:
Colour-change garnet, Sapphire, Spinel, lab-created alexandrite
(some sellers list any colour change gemstone as alexandrite)
Mohs Hardness:
8.5
Wearability:
Excellent
Birthstone:
June (shared with pearl and moonstone)
Spotting Synthetic (Lab-Grown) Alexandrite
Lab-created alexandrites have been on the market for decades and can look remarkably convincing. Here’s how to distinguish them from natural stones:
Sharp vs Soft Colour Change:
Natural alexandrite often shows a subtle or gradual colour shift with soft edges between hues. Synthetic stones (especially older types) may have a more dramatic and clearly defined colour change that seems almost too perfect.
Growth Structures & Inclusions:
Natural stones may show silky inclusions or fine parallel needle-like structures. Synthetics often show curved striae (growth lines) under magnification and may fluoresce in ways natural stones do not.
Common Treatments
One of alexandrite’s greatest advantages is its natural beauty. Most high-quality stones are untreated. This makes them especially appealing to jewellers and collectors who prioritise authenticity.
Lower-grade alexandrites may sometimes be enhanced to improve their appearance. Some are oiled or fracture-filled to boost clarity. In rare cases, a coating or colour enhancement may also be applied.
Durability Considerations
Alexandrite rates an impressive 8.5 on the Mohs scale. This places it among the most durable coloured gemstones. It resists scratching and abrasion exceptionally well.
The stone is also free from cleavage plains, so it doesn’t chip easily, making it ideal for everyday jewellery. However, like all fine gems, it’s still best to avoid sharp impacts.
Sudden temperature changes can affect its structural integrity over time.
Jeweller’s Setting Tips
Alexandrite is both tough and easy to set. But its dramatic colour change deserves thoughtful design decisions.
To bring out its full visual magic, use open-backed settings. These allow maximum light to enter, enhancing the stone’s shifting hues.
White gold and platinum can amplify the cooler green tones. Rose or yellow gold may enhance the warmer red side of its personality.
For high-value stones, prong or semi-bezel settings work well. They balance visibility and security, letting the colour play shine without compromising protection.
Care Instructions
Cleaning:
Mild soap and warm water are safe for most alexandrite. Use a soft brush to clean around settings.
Ultrasonic and steam cleaning is typically safe, but avoid it for stones with visible fractures, inclusions or those that have been treated.
Storage:
Store separately to avoid scratches, though alexandrite is tough, it can still damage softer gems in the same compartment.
Daily Wear:
Perfect for all jewellery types, including rings, thanks to its excellent wearability.
Market & Ethical Notes
Natural alexandrite is one of the rarest and most valuable gemstones on the market. Stones with a strong, vivid colour change are especially prized.
Most natural alexandrites are small. Typically under one carat. Even modest sizes can command high prices due to their scarcity.
Russia’s Ural Mountains is the original source, but alexandrite is also mined in Brazil, Sri Lanka, Tanzania and India. The colour change in Brazilian stones is often more muted and Sri Lankan alexandrite is usually paler than stones from other sources.
Synthetic alexandrite is widely available and much more affordable. It's often used in commercial jewellery settings.
As with all fine gemstones, ethical sourcing matters. Choose suppliers who are transparent about both treatments and origin.
Symbolic & Spiritual Meanings
Alexandrite is often associated with balance, duality, and transformation. Its ability to shift colour reflects flexibility and emotional insight. Some consider it a stone of joy, luck, and emotional strength.
It’s also said to align with the crown and heart chakras, connecting ones higher purpose with love and intuition.
Etymology
Alexandrite was named after Tsar Alexander II of Russia, as it was first discovered in the Ural Mountains in the 1830s, supposedly on the future tsar’s birthday. Fittingly, its red and green hues echo the imperial colours of Russia at the time.