Alexandrite is a rare variety of chrysoberyl prized for its remarkable color-change effect, appearing emerald-green in daylight and raspberry-red under incandescent light. It is commonly found as cyclic twins or tabular crystals within specific geological environments like mica schists. Collectors should look for a sharp, distinct shift in color and high clarity to distinguish it from imitations.
Is this alexandrite?
5-step field checkRun through these checks against the specimen in your hand. The more boxes tick, the more confident the ID.
- 1Test the hardnessTry to scratch alexandrite with a known reference. Alexandrite sits at Mohs 8.5, softer than the next harder reference, harder than the previous one.
- 2Check the streakDrag the specimen across an unglazed porcelain plate. Streak: white.
- 3Read the lusterHold the specimen under a strong light. Luster: vitreous.
- 4Match the color rangeCompare against the expected color range: emerald green, red, purplish-red, brownish.
- 5Look at form & habitCrystal system: orthorhombic. Typical habit: tabular crystals, often cyclic twins.
Often confused with
Alexandrite vs. its common look-alikes, and how to tell them apart in the field.
Often found alongside alexandrite
Minerals reported to co-occur with alexandrite. Spotting these in float or country rock is a strong cue you are in the right ground.
All properties
- Chemical formula
- BeAl₂O₄
- Mohs hardness
- 8.5
- Density
- 3.7-3.8 g/cm³
- Colors
- Streak
- White
- Luster
- Vitreous
- Transparency
- Transparent
- Crystal system
- Orthorhombic
- Crystal habit
- Tabular crystals, often cyclic twins
- Cleavage
- Distinct
- Rarity
- Rare
- Uses
- Gemstone, Collector
- Host rock
- pegmatites and mica schists
Where rockhounds find alexandrite
Classic worldwide localities
- Ural Mountains, Russia
- Minas Gerais, Brazil
- Sri Lanka
- Tanzania
- Zimbabwe
Field-hunting tip
Where it forms: pegmatites and mica schists. If you start seeing phlogopite, emerald, phenakite in float, you are in the right ground. Typical habit: tabular crystals, often cyclic twins. Train your eye for that shape before scanning the outcrop.
Common questions
How do you identify alexandrite?+
Where is alexandrite found?+
Is alexandrite safe to handle?+
What rocks look like alexandrite?+
What minerals are found with alexandrite?+
What kind of rock does alexandrite form in?+
What is alexandrite used for?+
Find alexandrite on the map
RockHoundR shows mapped rockhounding spots, access rules, and lets you log every find.
