Alexandrite Rings: The Colour-Changing Gemstone Explained
Alexandrite is one of the rarest and most extraordinary gemstones in the world. Its defining characteristic is a dramatic colour change visible to the naked eye: green to bluish-green in daylight, red to purplish-red under incandescent light. No other commonly available gemstone produces a colour shift of this magnitude, and fine natural alexandrite of significant size is among the most expensive gemstones per carat on the market. Lab-grown alexandrite replicates the colour change at a fraction of the cost, making the effect accessible to buyers who are drawn to the stone's unusual character.
TL;DR: Alexandrite changes colour between daylight (green) and incandescent light (red). Natural alexandrite of fine quality is extremely rare and expensive. Lab-grown alexandrite produces the same colour change at significantly lower cost. The stone rates 8.5 on the Mohs scale, making it suitable for daily wear. Bespoke alexandrite rings are available at À Vie Diamonds as a specialist commission.
What Causes the Colour Change
Alexandrite is a variety of chrysoberyl coloured by chromium. The chromium in alexandrite absorbs specific wavelengths of light in a way that produces green under daylight (which is relatively blue-white in spectral composition) and red under incandescent light (which has a higher proportion of red wavelengths). The human eye's sensitivity curve interacts with this absorption pattern to amplify the apparent colour difference, producing a shift that appears more dramatic than the spectral shift alone would suggest.
The quality of the colour change, measured by its completeness and the saturation of both colours, is the primary factor in alexandrite valuation. A stone that shifts from strong green to strong red is significantly more valuable than one that shifts between less saturated tones or from green to brown. Fine alexandrite from the original Ural Mountain deposits in Russia, where the stone was discovered in 1830, shows the most complete and saturated colour change of any known source.
Natural vs Lab-Grown Alexandrite
Natural alexandrite of fine quality is genuinely rare. Stones of 1ct and above with a strong, complete colour change from clean green to vivid red are extraordinary in the literal sense. A natural Ural alexandrite of 2ct to 3ct with strong colour change will command prices that put it beyond most engagement ring budgets without qualification.
Lab-grown alexandrite produces the same colour-change phenomenon through the same physical mechanism. The chromium content is the same; the colour change is real and identical in character to natural alexandrite. The cost is dramatically lower: a well-grown 1ct lab alexandrite with strong colour change is available at a fraction of the equivalent natural stone price.
For buyers whose interest in alexandrite is the colour-change effect itself rather than the geological provenance, lab-grown is the rational choice. For buyers who specifically value natural origin and rarity, natural alexandrite is the appropriate choice with the budget to match.
Hardness and Durability
Alexandrite rates 8.5 on the Mohs scale, making it one of the harder gemstones used in jewellery and genuinely suitable for daily ring wear. It sits between topaz (8) and corundum/sapphire (9), has no cleavage, and is not prone to chipping in normal wear conditions. For a coloured gemstone used in an engagement ring, alexandrite's durability is excellent.
What to Look for in an Alexandrite
The colour change is the primary quality indicator. A strong colour change from a saturated green to a vivid red, with minimal intermediate brown or grey tones, characterises a fine stone. Partial colour change, where the stone shifts between less saturated or more brownish tones, produces a less dramatic effect.
Clarity in alexandrite follows similar standards to other coloured gemstones: eye-clean is the practical target. Many alexandrites contain characteristic needle or silk inclusions that do not significantly affect the face-up appearance at normal viewing distances.
Cut is directed at maximising colour change visibility rather than brilliance in the way diamond cutting is optimised. A well-cut alexandrite shows the colour change cleanly across the face of the stone without dark extinction zones.
Alexandrite Rings at À Vie Diamonds
We produce alexandrite engagement rings and right-hand rings as specialist commissions. Given the rarity of fine natural alexandrite, most commissions use lab-grown stones where the colour change effect is the primary objective. For clients specifically seeking natural alexandrite, sourcing takes longer and carries a higher budget requirement. See our gemstones overview for more on specialist coloured stones, and get in touch to discuss an alexandrite commission.
Frequently Asked Questions
Does alexandrite really change colour? Yes, visibly and dramatically in fine specimens. The change from green in daylight to red in incandescent light is a genuine optical phenomenon caused by chromium absorption, not a surface treatment or enhancement.
Is alexandrite expensive? Natural alexandrite of fine quality is among the most expensive gemstones per carat. Lab-grown alexandrite is significantly more accessible and produces the same colour change effect. The choice between the two depends on whether natural origin or the colour change itself is the priority.
Is alexandrite durable enough for daily wear? Yes. At hardness 8.5 on the Mohs scale, alexandrite is harder than most coloured gemstones and has no cleavage, making it genuinely suitable for an engagement ring worn every day.
What metal suits alexandrite? White gold and platinum allow both the green and the red colour to read clearly without the metal's own tone interfering. Yellow gold can add warmth to both the green and red phases, which suits some buyers and not others.
Can I get lab-grown alexandrite in a bespoke ring? Yes. We source lab-grown alexandrite for commissions where the colour change effect is the priority. Get in touch to discuss specifications and availability.
Last reviewed: July 2026 · À Vie Diamonds