The retail replacement cost for a 1ct. alexandrite could be anywhere between $500 to $12,000 per carat. The intensity of the color change and the attractiveness of the colors are the most important factors in determining the value of an alexandrite. With a limited budget, a buyer can opt for a smaller cleaner stone with an excellent color change or a larger more included stone with a weaker color change. The price may be the same but, it is still the strength of the color change that should be the most important consideration.
The traditional view is that the best alexandrite shifts from emerald green to ruby red but in reality, this hardly ever occurs. Most alexandrites seem to show a good green in daylight or a beautiful red under incandescent light but few stones look good in every kind of light. Good quality alexandrite appears teal, emerald, or blue-green color under natural daylight and changes to purple-red or red under incandescent light.
It is rare to find alexandrites weighing over .25ct. and even stones weighing less than .50 carats can be worth several thousand dollars at retail prices. Stones over one carat may retail for $10,000/ct. while stones between 2.00 and 5.00 carats can fetch over $20,000/ct. Fine large alexandrites above five or six carats are extremely rare and top stones can sell for over $200,000.