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June - AlexandriteSee the chameleon split personality in June's Alexandrite, at Perrywinkle's. It changes from blueish-green in natural daylight to dark-rasberry when exposed to incandescent light -- revealing a clever twist from Mother Nature's bag-of-tricks.
Discovered in 1830 in Russia's Ural Mountains, the mine long ago dried up. Since then, only small traces of Alexandrite have been found, in Sri Lanka, Africa and Brazil, making it remarkably scarce.
You'd visit hundreds of jewelry stores and still be desperately-seeking a natural Alexandrite -- because most are man-made ones. But at Perrywinkle's, we feature beautiful, rich Alexandrites from our travels around-the-world.
Alexandrite Education:
Alexandrite, the birthstone for June, ranges in color from a bluish-green in natural daylight to beautiful raspberry in artificial light . This unique optical characteristic makes it one of the most valuable gemstones of all, especially in fine qualities. You will rarely see a collection of natural gem quality alexandrite's with as lively a color change as ones at Perrywinkle's. You could shop over 100 jewelry stores and never even see one alexandrite! Perrywinkle's carry's a huge inventory of these rare and beautiful stones starting at $500.
For alexandrite, the quality of the color change is most important. In fine examples, the change is typically one from a slightly bluish green to a purplish red. The quality of color change is often referred to by dealers in a percentage basis, with 100% change being the ideal. Stones that display a change of 30% or less are of marginal interest and are arguably not even alexandrite-Perrywinkle's would never carry such stones. In terms of clarity, alexandrite is comparable to ruby, with clean faceted stones in sizes above one carat being rare and extremely rare in sizes above 2'3 carats.
GEMOLOGY
Alexandrite is basically chrysoberyl, a mineral consisting of colorless or yellow transparent chrysoberyls and also iron, titanium and chromium all which help account for its spectacular color change. Like many other gemstones, alexandrite emerged millions of years ago in a metamorphic environment. But unlike many others, its formation required specific geological conditions. The chemical elements beryllium (a major constituent in chrysoberyl) and chromium (the colouring agent in alexandrite) have contrasting chemical characteristics and do not as a rule occur together, usually being found in contrasting rock types. Not only has Nature brought these contrasting rock types into contact with each other, but a lack of the chemical element silica (the second most common element in the Earth's crust) is also required to prevent the growth of emerald. This geological scenario has occurred only rarely in the Earth's history and, as a result, alexandrite crystals are very scarce indeed. They have a relatively good hardness (8.5 on the Mohs' scale) but are still prone to scratching.
HISTORY AND LORE
This rare gemstone is named after the Russian tsar Alexander II (1818-1881), the very first crystals having been discovered in April 1834 in the emerald mines near the Tokovaya River in the Urals. The discovery was made on the day the future tsar came of age. Although alexandrite is a relatively young gemstone, it certainly has a noble history. Since it shows both red and green, the principal colours of old Imperial Russia, it inevitably became the national stone of tsarist Russia.
Russia has remained the primary source of alexandrite since gems from the mines of the Urals became available on the market. When the Russian deposits were thought to have been exhausted, interest in the unique colour miracle decreased - especially since alexandrites from other mines hardly ever displayed the coveted colour change - . But the situation changed dramatically in 1987, when alexandrites were discovered in a place called Hematita in Minas Gerais, Brazil. The Brazilian alexandrites showed both a distinctive colour change and good clarity and colour. Thus the somewhat dulled image of the miraculous stone received another boost. The colour of the Brazilian stones is admittedly not as strong a green as that of Russian alexandrite, but the colour change is clearly discernible. Today Hematita is one of the most important deposits of alexandrite in economic terms. Occasionally alexandrite with chatoyancy is discovered there, an effect which has not yet been observed in Russian alexandrite. Alexandrites are also recovered from sources in Sri Lanka, but the hue of these stones compares less than favourably with that of the Uralian alexandrites. They appear green in daylight and a brownish red in artificial light. The Tunduru area in southern Tanzania has also produced some outstanding specimens since the mid-1990's. Alexandrites are also found in India, Burma, Madagascar and Zimbabwe. Although this stone is still considered a rarity, specialised gemstone dealers do stock it, especially since improved trade relationships between Russia and the rest of the world have ensured a better supply of Russian alexandrites to the market.
Uncut Alexandrite
ORIGIN
Russia, Brazil, Tanzania, Sri Lanka, Madagascar, India
PROPERTIES
Crystal system: Orthorhombic.
Refractive Index = 1.745 to 1.757 (This is the angle that light bends as it passes from the surface into the gemstone)
Hardness =8.5 (Moh's Scale) A hard stone, but subject to care because of internal liquid filled inclusions and fractures.
Specific Gravity =3.75 (The number of times heavier than water)
Species - Chrysoberyl
Optic Character =double refractive
Phenomena – Change of color (extremely rare)
Treatment – Not enhanced.
Ultrasonic: Usually safe.
Steamer: Usually safe.
Heat: Usually safe.
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