Gemstone guide
About Alexandrites
Alexandrites: their color, properties, origins, and treatments, with practical details for understanding each stone.
The short version
Alexandrite is the color-changing variety of chrysoberyl — bluish-green in daylight, shifting to purplish-red under warm incandescent light. Discovered in Russia's Ural Mountains in the 1830s and named for the future Tsar Alexander II, it became one of the most storied gems of the Russian court, its red and green echoing the imperial colors.
Fine natural alexandrite is rarer than diamond, ruby, or emerald — most jewelers will handle only a few significant stones in a career. With a hardness of 8.5 and a phenomenon no other gem reproduces so completely, it stands among the most collectible gemstones on Earth.
Formation
How Alexandrites Are Formed
Alexandrite is chrysoberyl — a beryllium aluminate — that formed where beryllium-rich pegmatite fluids reacted with chromium-bearing host rocks. Beryllium and chromium almost never occur together in nature, and that geological contradiction is precisely why alexandrite is so extraordinarily rare.
Chromium in the crystal lattice absorbs light in a narrow band, transmitting both green and red almost equally. Cool, blue-rich daylight tips the balance to green; warm incandescent light tips it to red. This “alexandrite effect” is the most complete color change found in any gemstone.
The classic deposits formed in the mica schists of the Urals; later discoveries in Brazil, Sri Lanka, and East Africa each produce stones with their own balance of change, tone, and clarity — with Brazil's Hematita deposit setting the modern standard.
Valuation
What Makes an Alexandrite Valuable?
Value is determined by several universal factors:
Value hinges on the color change: the ideal is a strong, complete shift from vivid bluish-green in daylight to raspberry purplish-red under warm light. Weak or brownish changes lower value sharply — both hues matter.
Alexandrite typically carries inclusions; eye-clean stones with a strong change are exceptionally rare. Chatoyant material cut as cat's-eye alexandrite is a prized rarity of its own.
Cutting alexandrite demands precision — the crystal must be oriented so both colors present face-up. Cushions and ovals are classic, balancing weight retention against the strength of the visible change.
Most gem-quality alexandrite is under one carat. Prices leap above that mark, and fine stones over three carats are auction-grade rarities.
Russian stones carry near-mythic status. Brazil's Hematita deposit produces the finest modern material, while Sri Lanka yields larger stones with a softer change, and East Africa adds a growing share of fine gems.
Alexandrite is typically untreated — one of the few major gems where enhancement is rare. Laboratory certification confirming a natural color change is essential at this level of rarity.
Origins
Major Alexandrite Sources
Russia (Ural Mountains)
The historic origin. Nineteenth-century Uralian stones remain the standard by which all alexandrite is measured.
Brazil (Hematita)
Discovered in 1987, the source of the finest modern material — strong, clean color change in well-saturated stones.
Sri Lanka
Produces larger crystals, often with a gentler day-to-night shift and excellent transparency.
Tanzania & India
Newer sources — Tunduru and Andhra Pradesh — supplying fine stones with vivid change to a supply-starved market.
Collectability
Why Collectors Value Alexandrites
Extreme rarity
Fine natural stones are rarer than diamond
Two gems in one
The most complete color change in gemology
Typically untreated
Natural, verifiable, and certifiable
Investment pedigree
Auction results climb decade after decade
Durability
8.5 on the Mohs scale — beyond every gem but corundum and diamond
Pricing & sourcing
Understanding Pricing & Transparent Sourcing
At Sapphire Row, we prioritize:
Accurate disclosure of treatments
Clear disclosure of lab reports
Transparency in pricing and origin
Bespoke
Source Your Perfect Alexandrite
Have a specific alexandrite in mind? Tell us what you're looking for — color, shape, carat weight, and budget — and we'll reply within 2 business days with options and a quote.