Yellow greenish to light yellow or brown chrysoberyl, which contains ferric iron as an impurity. Has an absorption spectrum band at first part of the violet at 444 nm, which can be seen in some chrysoberyl cat's-eye.
The theory that the eye contains three different groups of retinal fibers (cones) with maximum response to three primary colors to red-yellow, green, and blue violet, which are parts of the spectrum.
A dark gray, silvery luster, rare earth metallic element of the Periodic System with the symbol Y. Flammable when powder from. Used in alloys and as a metal deoxidizer.
Zonary growing of crystals bounded by plane crystal faces, which occur by slight variation in the composition of a crystal due to separation or interruptions of the crystal phases during growth.
The straight, parallel growth-lines in the internal structure of a gemstone with definite angles, usually seen in some stones, which occur by slightly variation in the chemical composition within the crystal due to separation or interruptions of the cryst
The mining of alexandrite in Russia lasted less than 100 years from the time it was discovered in 1833 to the early 1900’s. It was George Kunz, the gemologist/gemstone buyer for Tiffany & Co that probably did the most to popularize this unique gemst
Alexandrite is an expensive gemstone because it so rare and production has always been limited. For years, the only source for alexandrite was Russia. In the last 20 or 30 years several new discoveries of alexandrite have been reported but production of s
Chrysoberyl is the species name and Alexandrite is the variety name. Alexandrite is that variety of chrysoberyl that changes color as a function of the light source; green in daylight and red under incandescent light.
Cat's eye is the popular name for an optical effect known as chatoyancy in the gemological nomenclature. Microscopic needle-like inclusions inside the stone reflect a streak of light that appears to open and close as the stone is rotated -- hence the eye
The cat's-eye effect is caused by the reflection of light off of minute, parallel, needle-like rutile crystals or hollow tubes within the stone. Cat's eye inclusions are aligned parallel to the crystallographic axis and the stones are always cut as caboch
Several other well known gemstones, including diaspore, sapphire, garnet and spinel may also change color as a function of the light source but the color change of top alexandrites is distinctive and attractive under any light conditions.
Alexandrite is a trichroic gemstone which absorbs and reflects light differently in each of its three optical directions. Spectroscopic analysis reveals a different absorption spectrum for each of the three optical directions. The differences in absorptio
Unfortunately, most alexandrites show either a nice color in daylight or an attractive color under incandescent light. Rarely are both colors bright and vivid and often stones that change to bright red under incandescent light are only brown or almost bla
The retail replacement cost for a 1ct. alexandrite could be anywhere between $500 to $12,000 per carat. The intensity of the color change and the attractiveness of the colors are the most important factors in determining the value of an alexandrite. With
Along with diamonds, rubies, and emeralds, top quality alexandrites are among the most expensive gemstones in the world. In larger sizes over 4.00 or 5.00cts., Burmese rubies are more rare and expensive than alexandrites but in sizes below 1.00cts., alexa
Natural alexandrite is not better than synthetic alexandrite but natural alexandrite is very rare and uncommon in modern jewelry because it is hardly ever available and because it is too expensive for the general public to buy. Even lower quality more inc
Alexandrite cannot be improved by any kind of thermal treatment. Although some have tried, heat treatment does not seem to affect alexandrite at all. Some lower quality cracked alexandrites are oiled to hide the cracks but beyond that, alexandrite is not
It is very unlikely that even an old alexandrite ring could contain a natural alexandrite. Natural alexandrites, especially large clean stones are extremely rare and almost never available at any price. Most old inherited alexandrite rings are actually sy
Although Russian alexandrites have the most historical value, fine stones are occasionally available from deposits in Brazil, India, Tanzania, Madagascar, and Sri Lanka. Unfortunately, there has been little production of alexandrites from any deposit in r
With a hardness of 8.5, Alexandrite is a tough, hard, and durable gemstone that doesn't require any special attention. Still, even the hardest gemstones can shatter with a single well-placed blow so caution is always a good idea. Washing dishes with your
Fine alexandrites or alexandrite jewelry can be purchased from jewelers specializing in colored gemstones, at trade shows, from TV sellers, at high end jewelry auctions, or online from websites specialized in alexandrite. You would be unlikely to find a h
The most well known gemological laboratories are listed below and all of them are equipped to test alexandrite. Most gemological laboratories only identify gemstones, they do not appraise them.
First and foremost, we need to look at the quality and strength of the color change. A strong change where the colors are bright and attractive under any kind of light is most desirable. Many stones are either a beautiful green in daylight or a nice pinki
Alexandrite Guide website accessibility standards are in place with the intention of making the content accessible to the widest range of visitors, regardless of disability or impairment.
Fameo Online Jewellery Boutique specialises in design and manufacture of the gold, colour gemstone and pearl jewellery. Award winning jewellery designs and bespoke jewellery service. Provides jewellery collections showcase, buyers tips and jewellery guid
David Wein is an online fine jewelry store in association with Multicolour.com, the world´s most eclectic favourite online gemstone retailer.
David Wein brings together an exquisite range of fine jewelry at exceptional value. Visitors will find an e
An internationally acclaimed designer of fine jewelry. Recognized as the leading American jewelry designer, Yurman paved the way for a new era in fine jewelry with wearable, classic designs that carry a distinctive signature cable look. Available in over
Perlera Online Jewellery Boutique offers high fashion and timeless jewellery classics in an exquisite range of pearl jewellery, silver and coloured gemstone creations. Provides jewellery collections showcase, buyers tips and jewellery guides.
David Wein is an online fine jewelry store in association with Multicolour.com, the world´s most eclectic favourite online gemstone retailer.
David Wein brings together an exquisite range of fine jewelry at exceptional value. Visitors will find an e
An internationally acclaimed designer of fine jewelry. Recognized as the leading American jewelry designer, Yurman paved the way for a new era in fine jewelry with wearable, classic designs that carry a distinctive signature cable look. Available in over
GAA was formed in Sydney, on the 29th October 1945, the Association has been responsible for producing Australia’s gemmologists by educating and updating members of the gem and jewellery industry and the general public, about all aspects of gemstones an
As a member of the EGL USA Group, European Gemological Laboratory (EGL) is a full-service lab and offers a comprehensive array of gem identification, evaluation reports including customized reports of identification for rough and polished diamonds as well
Leading gemmological educational institution in Japan has been providing professional education in the field for the past 30 years.
Zenhokyo Laboratory is equipped with the most professional and advanced testing devices and systems, including inductive
Found at 1995, MSU Gemological Center is a part of MSU Department of Geology and co-founders of the Russian Gemological Society (2000), the Union of Modern and Antique Jewelry Appraisers, and member of the Russian Diamond Chamber.
First professional gemological laboratory to be established in Asia in 19978, - The AIGS Gemological Laboratory is a private, independent gemological laboratory, member of the Thai Gem and Jewelry Traders Association (TGJTA), and The International Colored
IT Gem Testing Laboratory (GIT-GTL), has been accredited by The World Jewellery Confederation (CIBJO) as the CIBJO Registered Laboratory since May 2000.
Dr. Eduard J. Gubelin, one of the forefathers of modern gemology, and who was a Founding Organizing Member as well as an Honorary Member of the International Colored Gemstone Association (ICA), passed away in Lucerne, Switzerland in March at the age of 91
SSEF laboratory offers analysis of precious stones and issue test reports for diamonds, coloured stones and pearls. It was recognized in 1978 by the International Confederation of Jewellers and Goldsmiths (CIBJO and also a member of the International Colo
The AGTA Gemological Testing Center is the natural coloured gemstone industry’s premier independent laboratory providing the industry and the public with a complete range of services, including gemstone identification, origin determination and pearl ide
American Gemological Laboratories is a unit of Collectors Universe, the leading provider of value-added authentication and grading services for high-value collectibles and gemstones, which was founded in 1986 and publicly traded since 1999. In 1977, Ameri
GIA is considered the world's most trusted name in diamond grading and gemstone identification. GIA’s D-to-Z colour-grading scale and Flawless-to-I3 clarity-grading scale are recognized by gem and jewellery professionals everywhere. And, by extension, t
Gem-A, which began as a Gemmological Committee of the National Association of Goldsmiths, first introduced a gemmology qualification in 1908 in order to encourage jewelers to understand the gems they were selling and to identify the fakes.
Jewellers Vigilance Canada (JVC) was established in 1987 as an independent non-profit association with a mandate to advance ethical practices, establish a level playing field for the Canadian jewellery industry and provide crime prevention education for t
The National Association of Jewelry Appraisers is the only appraisal association in the United States that devotes itself solely to the appraisal of gems, jewelry, silver flatware and hollowware.
The International Society of Appraisers (ISA) was formed in 1979 as a for-profit corporation focused on the education and professionalism of personal property appraisers. It became a non-profit corporation in 1994, and remains dedicated to enhancing the p