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Green in sunlight. Red in lamplight. Color-changing alexandrite is nature’s magic trick.

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Chrysoberyl Variety

Alexandrite is the color-change variety of the mineral chrysoberyl.

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Green by Day

Alexandrite is bluish green in daylight or fluorescent light.

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Red by Night

Alexandrite is purplish red in incandescent light or candlelight.

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Star-shaped Twin

This alexandrite specimen is made up of three interpenetrant crystals.

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Brazilian Gem

Brazil is one of the most important alexandrite sources.

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Re-entrant Angle

Notches marking the edge of each crystal are called re-entrant angles.

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Buyer's Guide

Colored stone professionals assess fine alexandrites by the extent of the color change they display and by the quality of the red and green hues they show under different lighting conditions.


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What To Look For

Color change is the most important quality factor for alexandrite

The most-prized alexandrites show a strong color change from bluish green in daylight and red to purplish red in incandescent light, with moderately strong to strong color saturation.

Cat’s-eye Alexandrite
Clarity is also important—most fine gems are eye clean

Alexandrites tend to contain few inclusions. There’s a dramatic rise in value for clean material with good color change and strong hues. Rarely parallel needle-like inclusions create a cat’s-eye phenomenon, increasing the alexandrite’s value.

Cut is one of the most important factors in appearance

Alexandrites are most often fashioned as mixed cuts, which have brilliant-cut crowns and step-cut pavilions. Alexandrite’s pleochroism makes it a challenge for cutters. When fashioning alexandrite, cutters orient the gem to show the strongest color change through the crown.

Carat weight allows for precise measurements

Most fashioned alexandrites are small, weighing less than one carat. Larger sizes and better qualities rise in price dramatically: Fine-quality stones in sizes above 5.0 carats are very expensive.

Alexandrite Quality Factors: The Comprehensive Guide

Tips & Advice

1. If it seems too good to be true, it probably is.

Natural alexandrite is rare and valuable. An inexpensive gem with a strong red-green color change is likely to be a synthetic or simulant.

2. Work with a jeweler you trust.

Judging the quality of alexandrite requires expertise. Look for gemological credentials. A jeweler who knows and loves alexandrite will welcome the challenge to find one that’s right for you.

3. When in doubt, get a lab report.

For a significant purchase an independent laboratory report can confirm that the alexandrite you are buying is natural.

4. Don’t expect to be able to match alexandrites easily.

Creating pairs or suites of alexandrite for earrings, a three stone ring, or a necklace is very challenging. Matching size, shape, color, and color change is particularly difficult.