Gemstone Alexandrite: Color Change, Value, Properties & Jewelry

Alexandrite is the color-changing type of chrysoberyl. In daylight, a high-quality stone appears green to bluish green. At warm artificial light, it takes on a red or purplish red hue. The stone (Mohs 8.5) is hard enough to wear in rings on a daily basis. Here I will describe what makes this phenomenon happen, how to tell the real one apart from the copy, and how to buy one.

Overview: Why Alexandrite Stands Out

The great gemstone exception It’s rare to find a gemstone that isn’t one color. Alexandrite isn’t. Take it from the sun-drenched window to the lamp, and the stone will change in your hand.

That single trick explains a lot. It’s why collectors chase it, why fakes are everywhere, and why a good stone costs so much. Let’s take it piece by piece.

Mineral group	Chrysoberyl (color-change variety)
Chemistry	BeAl₂O₄, with traces of chromium
Crystal structure	Orthorhombic
Mohs scale	8.5
Specific gravity	About 3.7
Refractive index is	About 1.746 to 1.755
Color change	Green to bluish green when exposed to daylight. Red to purplish red when exposed to incandescent light.
Birthstone of	June, with pearl and moonstone
Main sources today	Brazil, Sri Lanka, East Africa, India

What Is Alexandrite?

Alexandrite is a form of chrysoberyl that takes on different colors. Chrysoberyls can be nearly any hue. Very few are alexandrites however; for the stone to be alexandrite,  it must contain a certain amount of chromium and have a specific structure.

Where the Name Comes From?

Here is the story. In the 1830s, miners working in the Ural Mountains of Russia discovered a green crystal, dumped at the edge of the emerald mines near the Tokovaya River. It was, appropriately,  named after the future Tsar Alexander II.

Treat that as the popular account, not a fully documented fact. The original Russian deposits are mostly worked out, which is why old Russian stones are so collectible today.

Chemical Formula and Crystal System:

The formula is BeAl₂O₄, or beryllium aluminum oxide. A little chromium sits in place of some aluminum. The crystals are orthorhombic.

Don’t worry about memorizing that. One fact matters most: chromium makes alexandrite what it is.

Gemstone Alexandrite vs. Other Chrysoberyl:

Chrysoberyl comes in a few forms, and alexandrite is just one.

Plain chrysoberyl	Yellow, green or brown, no color change
Alexandrite	Green to red or purple color change
Cat’s-eye chrysoberyl	A sharp line of light, no color change
Alexandrite cat’s-eye	Color change plus a sharp line of light

So if a seller calls a yellow-green chrysoberyl “alexandrite,” ask to see it change in two different lights. No change, no alexandrite.

Why Does Alexandrite Change Color?

Picture it this way. A stone’s color is whatever light gets through. Alexandrite lets two kinds of light through, blue-green and red. It blocks most of the yellow in between.

Chromium Does the Work:

The yellow light is absorbed by the Chromium ions in the crystal, leaving two available windows, one for blue-green and the other for red.

The Light Picks the Color:

• Daylight has quite a bit of blue-green. So outdoors it appears green.
• A warm incandescent bulb leans red. The same stone glows red indoors.
• The stone never changes. The light does, and the stone just answers it.

See It for Yourself:

It is easy to evaluate a stone in three quick looks:

1. Position it close to a window in the daylight.
2. Place it under a warm lightbulb.
3. Repeat with LED or fluorescent light.

Jot down what you see each time. That third light can surprise you, because LEDs vary a lot.

Fair Viewing Tips:

Try to keep the stone at the same angle and distance to you each time. Use a plain white background then let your eyes relax after each lighting condition before making your decision.

Other Color-Change Stones:

Some sapphires, garnets, spinels and fluorites change color too. Their shift is usually weaker, and they’re different minerals.

Alexandrite	Green to red or purplish red	Chrysoberyl, hardness 8.5
Color-change sapphire	Blue to purple	Corundum, hardness 9
Color-change garnet	Greenish or brown to reddish	Garnet, usually softer
Color-change spinel	Varies by stone	Spinel, a different mineral
Color-change fluorite	Varies	Very soft, poor for rings

They’re lovely stones. They just aren’t alexandrite. When a seller uses the name loosely, ask for the exact species.

Alexandrite Properties:

Alexandrite is hard, fairly tough and strongly pleochroic. Here’s what each of those means for you.

Hardness and Toughness:

8.5, it takes a lot of scratches to mar the finish. Only a few common minerals are more scratch-resistant than this – corundum and diamond. And chrysoberyl is a little prone to cleavage,  even if you don’t find it (a hard tap in the wrong place can chip the stone).

Pleochroism:

Pleochroism means the stone shows different colors from different directions. Alexandrite does this strongly. That’s why cutters spend so long studying the rough. They want the best color change facing up.

Optical Properties:

The range of the refractive index is 1.746-1.755. The stone is doubly refractive. The specific gravity is approximately 3.7.

To the gemologist, these numbers are what help separate a real alexandrite from a fake. For instance, a corundum simulant will be more dense and exhibit different optical characteristics.

Alexandrite Cat’s-Eye:

Some alexandrite shows a bright line of light that glides across the stone. That’s chatoyancy. A stone with both the color change and a crisp cat’s-eye is one of the rarest gem effects out there.

Alexandrite Meaning and Beliefs:

What follows are traditions and personal beliefs. They aren’t scientific facts.

June’s Birthstone:

June’s other gemstones, aside from pearl and moonstone, are alexandrite. Along with pearl and moonstone, alexandrite is one of the June birthstones. Pearl and moonstone signify tranquility and intuition, and alexandrite signifies change.

Symbolism:

People tie the color change to balance and adaptability. The stone moves between two colors, so it’s become a symbol of duality: light and dark, past and future.

Zodiac and Chakra Ideas:

Certain astrology groups link alexandrite to Gemini and Cancer. New age crystal groups also use alexandrite with the crown and heart chakras. Because there is some conflicting information on the above topics, use your own discretion and experience to relate.

No stone can scientifically be said to be healing. If that is important to you, it should be kept traditional.  else, go for the quality of gemstone.

Where Is Alexandrite Found?

Where a stone comes from changes how it looks. Sometimes it changes the price too.

Russia (Urals)	Historic source. Stones are rare and collectible
Brazil	Strong change is possible. Often small
Sri Lanka	Often a softer change, with larger stones available
East Africa (Tanzania and others)	Good change is possible. Clarity and size vary
India	Good change appears, with varying quality

Does Origin Raise the Price?

It can. Russian stones carry a premium for their history and rarity. But a seller’s story isn’t proof. Origin should come from a laboratory report.

And keep this in mind: a great stone from Sri Lanka can beat a weak one from Russia. Judge the stone in front of you first.

How Is Alexandrite Mined?

Sources of Alexandrite the stone is obtained from hard-rock deposits and river gravel, also called alluvial deposits. Miners extract the stones by digging,  washing the gravel and grading the stones by hand.  Extraction is handled differently in each area, and much of the work is artisanal.

Inquire about the stone’s source and how the seller knew.  Documentation trumps storytelling.

How to Identify Real Alexandrite?

There’s not a single test to confirm it’s real. You’ve got to check a few boxes, a little like making a case.

Watch the Color Change in Different Lights?

If the gemstone is transitioning from green to a slightly red or purplish red, that’s the sign. Test the gemstone in daylight, incandescent and LED. Request the jeweller sends you a short video in each light source. Photos can be edited, but it’s very difficult to fake a video.

If the change is dull, or the stone becomes brown or gray,  anticipate a weaker stone.

Look Inside the Stone:

Ask for a 10x loupe, or have a gemologist examine under a microscope. Natural stones frequently exhibit ‘needles, ‘fingerprints,’ or small crystals. Curved growth lines are typical of a lab-grown stone. Round ‘holes’ or ‘bubbles’ indicate glass.

Know the Three Categories:

Natural alexandrite	Formed in the earth	Highest-value category
Lab-grown alexandrite	Real chrysoberyl, grown in a lab	Chemically alexandrite. Should be sold as lab-grown
Simulant	A different material, such as synthetic color-change corundum	Not alexandrite. Different density and optics

Sellers sling around ‘lab-created’ and ‘synthetic’ far too freely. Lab-grown alexandrite is a genuine chrysoberyl. A simulant is anything but. So be clear and get it in writing – which one is it?

Check the Optical Properties:

The actual alexandrite has a RI close to 1.746–1.755 and a specific gravity about 3.7. Corundum simulants run higher on both. A gemologist can measure this fast. At home, you can’t do it reliably.

Get a Laboratory Report:

Get the report for a large purchase from a qualified lab like GIA, SSEF or Gübelin. Confirm the report lists the species,  has the report state whether the gem is natural and includes a color change description. No report on a stone over one carat? That’s a warning sign.

Verify the report number with the lab. Then read what it actually covers. Identification, treatment and origin are separate conclusions, and one report may state only some of them.

What a Photo Can’t Tell You?

A photo can’t show density, refractive index or inclusions. It can’t prove the color change either. Use photos to shortlist stones, not to decide.

Is Alexandrite Treated?

Most natural alexandrite is sold untreated. But treatments exist, so you should ask.

Fracture filling is one example. Fillers can affect durability and cleaning. A lab report should say what the lab found. Don’t assume anything. Get the treatment status in writing, and compare it with the report.

Alexandrite Price and Value:

Prices swing widely, and sources disagree. No single price per carat exists.

What Drives the Price?

• Strength of change in colour: A strong change in colour stands as far higher in value than a weak one.
• Color of the body: Plain green and plain red or purple should beat muddy colors.
• Size:  Price per carat increases more sharply as the size goes beyond 1 carat.
• Clarity: Eye-clean stones are more expensive.
• Origin and documents: A lab-supported origin adds confidence.
• Natural or lab-grown: Natural stones cost much more.

Price Examples From Public Sources:

These are asking prices and published guides, not completed sales.

International Gem Society price guide	Top-quality natural, up to 1 ct	About $1,818 per carat (average)
Listing on the web	GIA-sanctioned natural, 3.99 CT	$12,799, for a total of (approximately 3,200 dollars for each CT)
Online listing	GIA has listed certified natural 8.41 carat	$59,825 in total (about $7,100 per carat)
Up for sale on the internet	Stones listed with GIA report Sri Lankan,	8.73 ct $167,911.72 list price (aprox $19,200 per carat)

Not every listing showed a date, so re-check these before you rely on them. Some dealers publish far higher figures for fine Russian or Brazilian stones. Treat those as dealer claims, not market facts.

Why Size Matters So Much?

Price per carat doesn’t increase evenly If you’re purchasing stones above one carat,  pristine, well-colored stones become increasingly scarce, so an 8-carat stone will command a much higher per carat price than a 1-carat one,  of comparable color and clarity.

Lab-Grown Prices:

Lab-grown alexandrite is far cheaper,  as there are no supply constraints from mining. This makes them a reasonable alternative if the appearance appeals and you don’t care if it’s natural.  Be certain, however,  the seller specifies it is lab-grown.

A Quick Estimate:

For a first estimate on a natural stone, try our Gemstone Price Calculator. It covers alexandrite, uses fixed multipliers and doesn’t use live market data. Compare its result with real listings. You can also read the IGS alexandrite price guide.

Is Alexandrite an Investment?

I can’t say for sure. It depends on prices and you can’t guarantee the return.  If you buy a stone that you want to own you should treat any resale value as a bonus.

Where to Buy Alexandrite?

Buy from people who show their evidence.

Online Dealers:

Look for dealers who give third-party laboratory reports, clear photos, videos in different lights and a real return policy. Make sure the report number matches the stone.

Jewelry Stores:

A store with gemological know-how lets you see the stone in person. You can test the change under the shop lights, then step outside.

Auctions and Shows:

Auctions and gem shows can turn up rare stones. They carry more risk, though. Ask for documents and do your homework first.

Questions to Ask Any Seller:

1. Is this stone natural, lab-created,  or a simulant?
2. Is laboratory report available and could I check the number?
3. Can you send a video in daylight, incandescent and LED light?
4. Is the stone treated in any way?
5. What’s your return policy?

Want a second opinion on a stone? You can contact us.

Red Flags:

• No report on an expensive stone
• A color change shown in only one light
• “Synthetic” used with no explanation
• A price far below similar stones
• Pressure to buy fast

Common Buying Mistakes:

Most mistakes come from rushing. These are the ones that cost people money.

Judging by Color Alone:

A green or red stone isn’t alexandrite just because of its color. Plenty of stones share those shades. Check the change and the report.

Trusting One Photo:

One photo shows one light. It tells you nothing about the change.

Treating Lab-Grown as Fake:

Lab-grown alexandrite is a real stone. It’s just not natural, and it should cost much less. An undisclosed lab-grown stone is a problem. A disclosed one is a fair product.

Ignoring The Setting

A great stone in a weak setting can get damaged. Ask how the setting protects it.

Alexandrite Jewelry and Everyday Wear:

While similar, alexandrite has a hardness of 8.5 on the Mohs scale of hardness and is also suitable to be worn in rings, earrings, pendants and bracelets (preferably with a protective setting).

Engagement Rings:

Alexandrite as a ring choice Alexandrite is a wonderful engagement ring. Opt for a bezel or a sturdy prong setting,  then question the jeweler how he will safeguard the stone. The change is visible in oval, cushion and spherical cuts.

Which Metal Looks Best?

The style of setting around the stone can influence the color appearance. If possible, try the stone in more than one setting before you buy.

Heirloom and Custom Pieces:

Alexandrite is tough and fine for heirloom jewelry.  Save the certificate with the jewelry. It will help in selling and insuring the piece.

How to Clean and Care for Gemstone Alexandrite?

Alexandrite is easy to look after. A few habits keep the color change sharp.

Cleaning Steps:

1.  Submerge the article in a solution of warm water with a few drops of delicate dish-washing liquid and leave for a few minutes.
2.  Use a soft toothbrush and gently brush it.
3.  Wash with plain cold water.
4.  Dry it with a soft, lint-free cloth.

What to Avoid?

1. Harsh chemicals, perfumes and chlorine
2. Strong scrubbing, abrasive brushes
3. Steam cleaners
4. High variability in temperature.

For clean stones ultrasonic cleaning should be fine but check with your jeweler, first.  Never use it on stones that have fractures or filling.

Storage:

Keep the item in a soft pouch or in its own compartment (away from other stones). When stored with other jewelry, it should be away from jewelry with hard stones. Have the prongs and setting checked once a year.

Insurance and Appraisal:

For a really good stone, have it professionally appraised in writing and review once every few years. Price points.  Have the report and the receipt together.

Buyer Checklist:

1. Identify the exact species: Natural, lab-grown or simulant.
2. Request a lab report and double check the number.
3. Observe a change in the color in daylight, Incandescent, and LED light.
4. Demand videos in addition to photos.
5. Show me the treatment status in writing.
6. Compare prices for similar stones, asking and sold.
7. Always inspect for chips, cracks and surface wear.
8. Read the return policy.
9. Walk away from anyone who promises investment returns.

You can browse our other guides in the GemHub.

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