INFORMATION ABOUT ALEXANDRITE IN ESTATE JEWELY AND VINTAGE JEWELRY (Chrysoberyl, Cat's-Eye)
ORIGIN OF NAME
Alexandrite is known as the gemstone of the Czars. Though alexandrite and cat's-eye look very different they are from both from chrysoberyl and are therefore the same mineral. Chrysoberyl is very hard and durable and is an excellent gemstone for jewelry. In hardness, chrysoberyl follows behind diamonds and corundum.
BIRTHDAYS AND ANNIVERSARIES
Alexandrite is the alternate birthstone for June. Cat's eye is used to celebrate the 18th wedding anniversary.
ORIGIN OF NAME
Named for Czar Alexander II of Russia. Alexandrite was name after Czar Alexander II's as it was found on his birthday. Chrysoberyl derives form the Greek word "chrysos" referring to the stone's golden color and beryl mineral.
In 1789, A.G. Werner, identified chrysoberyl, as a unique mineral species. Previous to this time it was considered to be a part of the beryl family. Cat's-eye has held the longest history. It was known in Rome by the end of the first century, but it has been admired and respected longer in the Orient. In Europe, it regained attention when it was given by the Duke of Connaught to the Princess Louise Margaret of Prussia.
Alexandrite was found in the Ural Mountains in 1830.
The transparent and more common variety of chrysoberyl, the transparent greenish yellow form, was found in Sri Lanka and Brazil.
ESTATE JEWELRY, VINTAGE JEWELRY AND ANTIQUE JEWELRY USAGE
This gemstone became popular in the eighteenth and nineteenth century. It may be found in Spanish and Portuguese estate jewelry. This type of chrysoberyl was used often in jewelry during the Victorian and Edwardian Jewelry eras. Alexandrite regained popularity for fine jewelry usage in the 1980s and may be found in contemporary alexandrite estate jewelry.
The native Sri Lanka population believed that cat's-eye protected its wearer from evil spirits. Hindus believed that it protected the bearer's health and guarded him against poverty. Old oriental beliefs were that when it was pressed against the forehead that it would help foresight. Alexandrite is considered a gem of good omen in Russia, and is the only gem considered a talisman in Russia as late as the 19th century.
Chrysoberyl crystallizes in and around pegmatites rich in beryllium. Deposits commonly form as alluvial concentrations from weathered pegmatites.
A distinct color change and intense color are the most important factors for the stone's value. Also of importance are size and clarity. Flaws do diminish the value. Fine quality stones which exceed 5 carats are both rare and expensive. Alexandrite cat's eye is one of the rarest and most costly of gems. A rich honey colored cat's eye brings the largest value. The eye band needs to be sharp, narrow and centered for the greatest value. The eye should open widely in oblique illumination and close in direct illumination. The more transparent the stone, the greater the stone's value. Stones over 15 to 20 carats are rare and very expensive.
Chrysoberyl is found in Brazil and Sri Lanka. The major source is Minas Gerais in Brazil, since 1987 it has been the largest producer of alexandrite. The Russian deposits near Sverdlovsk and near the Sanarka River are now apparently exhausted. The Sri Lanka alexandrite has a more attractive green color, however, the Russian alexandrite has a better color change and a finer red color under indoor lighting. There are also chrysoberyl deposits found in Russia, Tanzania, Sri Lanka, Zimbabwe, Madagascar and Myanmar.
Ultrasonics and steam cleaners are generally safe when the stone has good clarity. Chrysoberyl is stable to heat and light and does not normally have a reaction to chemicals.
VARITIES OF CHRYSOBERYL :
ALEXANDRITE: First discovered in the Ural Mountains in Russia. Alexandrite looks green in sunlight and purplish-red in incandescent light (light bulbs). The gemstones color is also important, as red and green are the colors of the Russian Imperial Guard. Natural alexandrite is very rare. Synthetic alexandrite, synthetic sapphires and synthetic spinel with color change are more frequently found and sold. Alexandrite may be found in antique and estate jewelry from Russia.
CAT'S EYE: cat's-eye has been popular for centuries in the orient, but only became popular in Europe in the late 19th century when it was given as an engagement ring by the Duke of Connaught gave an engagement ring to Princess Louise of Margaret of Prussia. The current use of cat's eye is mainly in men's rings. Other stones that may have a "cat's-eye" appearance are quartz and tourmaline. Cat's eye may also show a color change, though this is very rare.
Crystal system: Orthorhombic
Cleavage: indistinct or none
Refractive Index 1.74 - 1.76
Optic: double refracting and biaxial positive
Specific Gravity: 3.70 - 3.76
With a hardness of 8.5, on the Mohs' Scale, overall is a durable natural gemstone and is excellent to wear. Generally alexandrite and cat's-eyes are not treated, but occasionally they may be treated with fillers.
The measure of relative hardness, Mohs' Scale, defines common stones and minerals for the hardness and durability.