ENCYCLOPEDIA · SKYJEMS

Colour-Change Alexandrite — GIA-Certified

Key concepts

colour change alexandrite, gia certified alexandrite, chrysoberyl alexandrite, alexandrite colour change, natural alexandrite

Alexandrite is the colour-change variety of chrysoberyl: a stone that reads green to bluish-green in daylight and shifts toward purple or purplish-red under incandescent light. The effect comes from chromium. Skyjems holds a colour-change alexandrite selection, and where a stone carries a GIA report, that report confirms the variety and describes the colour change.

"Emerald by day, ruby by night" — what that phrase is worth

You will read that a fine alexandrite goes emerald green by day and ruby red by night. That stone does not exist. Not in a collection, not in a museum, not at any price. Even the finest Russian material from the original Ural deposit runs more yellow than emerald in daylight, and its second colour carries a heavy purple rather than the red of a ruby.

The honest top of the market is a green to purplish-red change. That is what a superb alexandrite does, and it is worth wanting. Anyone promising you emerald-to-ruby is either repeating a line they have not tested or selling you something else.

Judging the change

Two variables outrank the usual four Cs: the strength of the shift and the quality of both colours. The range is real and wide. Much of the material moves from a yellowish green to a greyish purple; some moves green to a yellowish brown, which is the weak end of the species. A stone that goes from a clean blue-green to a distinctly reddish purple sits at the top of what is genuinely available, and it is uncommon.

So the question to ask is not "does it go green to red" but "how decisive is the shift, and do I like both colours it lands on".

Origin — and the Russian namesake

Alexandrite was named for Tsar Alexander II after its 1830s discovery in Russia's Ural Mountains; that original source is largely depleted. Today's material comes chiefly from Brazil, Sri Lanka (Ceylon), Madagascar and India. A GIA report describes the colour change reliably; formal origin determination on alexandrite is less routine than on sapphire or ruby, so we lead with the documented phenomenon and weight rather than over-asserting a mine of origin.

Reading the lab report

A GIA report on alexandrite states species = chrysoberyl, variety = alexandrite, and characterises the colour change; treatment is typically recorded as none, as fine alexandrite is rarely enhanced. GIA is the laboratory we lead with, and where a stone carries a GIA report we list it on the product page. Other alexandrite we hold is assessed in-house and sold on its own merits.

Four things to check

(1) the report confirms the stone is natural alexandrite and describes the change; (2) the shift is decisive rather than a faint grey drift; (3) both the daylight and the incandescent colour are attractive in their own right; (4) clarity is eye-clean to lightly included and the weight matches the report.

Skyjems inventory snapshot

Browse alexandrite at /collections/alexandrite — a selection across Brazilian, Ceylon, Madagascan and Indian material. Skyjems' selection changes as stones are added or sold; review each current listing for its own documentation.

Private viewings and bespoke

Contact Skyjems at +1-416-366-3335 or request a private viewing.