orthorhombic Synthetic synthetic chrysoberyl

Synthetic Alexandrite (Czochralski Boule)

BeAl2O4:Cr

Crystal Structure

CDL Notation

 #! Species: Synthetic Alexandrite (Czochralski)
#! System: Orthorhombic (mmm)
#! Habit: Chrysoberyl habit from Czochralski boule
orthorhombic[mmm]:{110}@1.0 + {010}@0.6 + {111}@0.4

Crystal System orthorhombic

Point Group mmm

Crystal Forms (3)

{110} {010} {111}

Quick Facts

Hardness

8.5

Specific Gravity

3.71

Refractive Index

1.744

Optical Character

Biaxial +

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Physical Properties

Crystal Systemorthorhombic

Hardness (Mohs)8.5

Specific Gravity3.71

CleavageDistinct on {110}, poor on {010}

FractureConchoidal

LustreVitreous

Optical Properties

Refractive Index1.744

Birefringence0.011

Optical CharacterBiaxial +

Dispersion0.015

Pleochroismvery strong: green / orange / purple-red

PhenomenonColour change (alexandrite effect)

FluorescenceStrong red (LW UV)

Origin & Identification

OriginSynthetic

Growth MethodCzochralski

ManufacturerCreative Crystals, Seiko

First Produced1972

Diagnostic FeaturesCurved striae, gas bubbles (Czochralski method), too-perfect colour change, no natural inclusions, may show strong red fluorescence