Alexandrite: The Colour-Changing Gem and How to Buy It
Alexandrite jewellery is built around one quiet bit of magic: a stone that shifts from green in daylight to a soft red or purple under a lamp. It is the rare colour-change variety of the mineral chrysoberyl, and it sits among the most sought-after coloured gems in the trade. At Vanhess Jewellery in Coquitlam, BC, alexandrite comes up most often with June babies and with collectors who want something that does not look like everyone else's ring. Here is how to understand it and how to buy it well.
The colour change, and why it happens
The headline feature is the shift. According to GIA, alexandrite shows a lovely green in daylight or fluorescent light, then changes to a brownish or purplish red under the incandescent light of a lamp or candle flame. The effect is so distinctive it has its own name: the alexandrite effect. It happens because the stone absorbs light unevenly, and the balance tips depending on whether the light source is rich in blue (daylight) or rich in red (a warm bulb).
Not every alexandrite changes the same amount. Some flip cleanly from green to red. Others shift only slightly, from a greyish green to a muddy purple. The strength and cleanliness of that change is the single biggest thing that separates an everyday stone from a remarkable one.
June birthstone, and tough enough for daily wear
Alexandrite is a birthstone for June, alongside pearl and moonstone, per GIA. That makes it a popular alternative for anyone born in June who wants a faceted coloured stone rather than a pearl.
It also holds up. Alexandrite rates 8.5 on the Mohs hardness scale, with excellent toughness and no cleavage, the tendency to split when struck. GIA calls it a good choice for rings and other pieces that take daily wear. For comparison, that puts it above quartz and just below sapphire, so it shrugs off the knocks that would scratch a softer stone.
Natural versus lab-created
Natural alexandrite is genuinely rare, and fine large stones command serious prices. Lab-created alexandrite is the same material grown in a controlled setting, so it has the same hardness and a real colour change at a fraction of the cost. Neither is fake. The difference is origin and price.
My honest take: if you want the romance and the investment value of a natural stone and you have the budget, buy natural and get it documented. If you mostly want the colour-change party trick in a ring you will wear hard, lab-created gives you the look and the durability without the heart-stopping price. Just make sure whoever sells it to you discloses which one it is in writing. Reputable sellers always will.
| Factor | Natural alexandrite | Lab-created alexandrite |
|---|---|---|
| Mohs hardness | 8.5 | 8.5 |
| Colour change | Yes, varies by stone | Yes, often strong and consistent |
| Rarity | Very rare, especially in larger sizes | Readily available |
| Relative price | High to very high | Much lower |
| Best for | Heirlooms, collectors, documented value | Everyday wear, the effect on a budget |
A little history, and why fine stones are scarce
Alexandrite was first found in the Ural Mountains of Russia in the 1800s, and those early stones set the standard the trade still chases: a clean shift from a deep emerald green to a rich raspberry red. Russian deposits were largely worked out long ago, and later finds in Brazil, Sri Lanka, and East Africa have helped supply, but top material with a strong, complete colour change in a larger size remains genuinely scarce. That scarcity is the whole reason natural alexandrite sits among the more expensive coloured stones, ounce for ounce, and why buyers should not expect a big, vivid natural stone at a small price. If a deal looks too good, it is almost always lab-created, and it should be sold to you as such.
How to judge the strength of the colour change
When you look at a stone, judge four things. First, how complete the change is: a true green-to-red flip is worth far more than a green-to-purple-grey shadow. Second, how saturated the colours are in each light; pale washed-out hues are less prized than vivid ones. Third, clarity, since eye-clean stones cost more than included ones. Fourth, the size, because fine natural alexandrite climbs in price steeply as it gets larger.
Test it yourself. Look at the stone by a window in daylight, then walk it under a warm incandescent or candle-style bulb. Watch how far and how cleanly it travels. We do exactly this at the counter, moving a stone between our daylight lamp and a warm bulb, because the change is the whole point and you should see it before you pay for it. One more thing worth knowing: a stone can look great in the shop's lighting and underwhelm at home, so view it under the kind of light you actually live with, whether that is warm bulbs in the evening or cool daylight by a window. The lighting in your house is the lighting the stone will perform under for years.
Key Takeaways
- Alexandrite is a colour-change chrysoberyl: green in daylight, red or purple under warm lamp light.
- It is a June birthstone, alongside pearl and moonstone.
- At 8.5 on the Mohs scale with excellent toughness, it stands up to daily wear in rings.
- Natural stones are rare and expensive; lab-created stones share the same hardness and effect for far less.
- The strength and cleanliness of the colour change drives value more than any other single factor.
Frequently Asked Questions
What is alexandrite and why does it change colour?
Alexandrite is the rare colour-change variety of the mineral chrysoberyl. It looks green in daylight or fluorescent light and turns brownish or purplish red under incandescent lamp or candle light. GIA calls this the alexandrite effect; it happens because the stone absorbs light differently depending on the light source.
Is alexandrite hard enough for an everyday ring?
Yes. Alexandrite rates 8.5 on the Mohs hardness scale and has excellent toughness with no cleavage. GIA describes it as a good choice for rings and other mountings that face daily wear, sitting just below sapphire and ruby in hardness.
Is lab-created alexandrite real?
Yes. Lab-created alexandrite is genuine alexandrite grown in a controlled setting. It has the same chemistry, the same 8.5 hardness, and a real colour change. It costs far less than natural stones. A reputable seller will always disclose in writing whether a stone is natural or lab-created.
What makes one alexandrite worth more than another?
The colour change. A complete, vivid green-to-red shift is far more valuable than a faint green-to-grey one. After that, saturation, clarity, and size drive the price, with fine natural stones rising sharply in cost as they get larger.
Sources
- GIA — Alexandrite Description, accessed June 2026
- GIA — June Birthstones, accessed June 2026
- Geology.com — Mohs Hardness Scale, accessed June 2026
Data sourced June 2026. If you spot something out of date, let us know and we will update the guide.
Visit Vanhess
We are a family-run studio at 2929 Barnet Highway, Unit 2424, in Coquitlam, with an on-site goldsmith. If alexandrite has caught your eye, come in and we will move a stone between daylight and warm lamp light so you can watch the colour shift before you buy. Look through our rings and pendants for setting ideas, then call +1 (604) 653-6449 to talk options or commission a custom piece.
