Question 1

Why does alexandrite change colour?

Accepted Answer

Chromium in alexandrite absorbs yellow light and transmits both green and red almost equally. Daylight is rich in blue and green wavelengths, so the stone appears green, while incandescent light and candlelight are richer in red, so the stone appears red or purplish red. The balance is delicate, which is why the strength of the change varies so much from stone to stone.

Question 2

How can I tell if alexandrite is natural or lab-grown?

Accepted Answer

It is often not possible without laboratory testing. Laboratory-grown alexandrite has the same composition and properties as natural material, and separation relies on inclusions, growth features and trace element chemistry. Some synthetic stones show clear evidence under magnification, others need advanced instruments. For any stone of value, ask for a report from a recognised laboratory confirming natural origin.

Question 3

Where does the best alexandrite come from?

Accepted Answer

Russian alexandrite from the Urals has the strongest historical reputation, and fine Brazilian stones from Minas Gerais are also highly regarded. Sri Lanka, India and East Africa produce good material as well. Origin is a laboratory opinion based on inclusions and chemistry, and quality varies within every source, so the colour change and overall appearance of the individual stone should come first.

Question 4

Is alexandrite a good stone for everyday jewellery?

Accepted Answer

Yes. At 8.5 on the Mohs scale, alexandrite is harder than most coloured gemstones apart from corundum, and it has good toughness with no pronounced cleavage. It is suitable for rings worn daily. Stones with filled fractures need gentler care, so avoid ultrasonic cleaners and harsh solvents unless you know the stone is untreated.

Alexandrite