Alexandrite

Discovered in 1830 in the Ural mountains of Russia. Alexandrite is also found in Sri Lanka, Brazil, India, Tanzania, Zimbabwe, and most recently in Madagascar. The alexandrite variety of chrysoberyl is one of the rarest and most sought after of all gems.


Facts

Color Key:Color changing from green to red.
Refractive Index:1.741 - 1.760
Chemical Composition:BeAl2O4
Hardness:8.50
Density:3.73
Crystal Group:Orthorhombic
Ocurrence:Tanzania, India, Russia, Madagascar, Sri Lanka, Zimbabwe, Zambia.
Sign of the Zodiac:Gemini
Month of the year:June
Planet:Mercury

Alexandrite is chrysoberyl that changes color when viewed under different lighting sources. Usually blue-green in daylight and purplish-red under incandescent light, alexandrite is a beautiful stone and one of the birthstones for those born in the month of June.

The degree of color change is the barometer of top quality alexandrite. Most desirable stones exhibit rich color under any kind of light. Clarity, cut, and size are the next most important considerations after color. Large stones are always rare and as a result more valuable. Cutting and proportions are important but a careful balance between weight retention, shape, color change, and careful positioning of unremovable inclusions is required to produce the most valuable stone. A poorly cut 1ct.+ stone may be worth more than a perfectly cut .90ct. stone so cutting and preforming require careful attention in order to maximize yield and value.

Russian alexandrites have the most historical value but fine stones are available from several other deposits. Brazil, India, and Tanzania produce the bulk of today’s production but alexandrites are also found in Sri Lanka and Madagascar. Brazilian stones typically show the best reds under incandescent light but Indian stones are well known for their superior bluish green daylight colors. Tanzania and Madagascar seem to produce the largest stones and some of the stones are exceptional. There is currently hardly any production of Russian stones.

The color change phenomena of alexandrite is a result of chromium +3 ions and the way they are absorbed and reflected. In rubies the chromium absorption band is around 550 nanometers and in emeralds, the band is around 600nm. In alexandrite, where the band is at 580nm and right between ruby red and green emerald, the stone is balanced between them. When the light is balanced (daylight), the stone will be green but when the light source is reddish (incandescent), the stone appears red.

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Pearls

"The pearl is at the height of its perfection when taken from the shell; from that moment it never improves. When it is drawn from the depths of the ocean bythe hand of man and given to the charmed gaze of the world, it is as complete and perfect in its way as the most beautiful work of art, and, whether as tiny as the point of a pin or as large as a marble, it is awlays as perfect, fully formed individual; it is always in its maturity."Kari Pearls

Visit the pearl experts at Kari Pearlsand discover who found the first pearl? When did he discover it and what were his emotions? Was it found by primitive man? Learn about the wide variety of pearls, how to determine their value, how to care for and clean them. When I need information about pearls I always check out Kari Pearls, the most comprehensive pearl resource I have found.