Make sure that it is thoroughly dry before putting it into its storage space. It is best cleaned using warm soapy water and perhaps a very soft brush if there is any dirt lodged in its setting. Although cymophane is a relatively tough stone it should not be subjected to excessive heat, ultrasonic cleaners or steam jewelry cleaners. A good stone, from Sri Lanka for example, should never need to be irradiated but if the stone has been treated it should always be disclosed to the potential buyer. Such a treatment can indeed bring the the color of a rather wishy-washy stone up to the desirable honey brown, and this particular practice was quite popular in the 1990s in the Asian jewelry market. Some stones exhibiting less than optimal chatoyancy or color can be irradiated. It should be mentioned that there is no such thing as a transparent cat’s eye, and that the only cut that will produce the desired effect is a cabochon. However, the golden tones are more valued in the marketplace. Some people prefer the green variety because the color is more similar to the actual eye color of many cats. This milk and honey effect is especially important in evaluating the overall quality of the stone.Īlso, the thinner, straighter, and more contrasting the white stripe, the more valuable the stone in question. As the stone is moved in relation to the light source, these two colors will swap positions. When you direct the light source at one of these stones, one side of the stripe will be a milky whitish color while the other side of the stripe will remain gold. As you can imagine, this technicality often causes much confusion!Ī particularly desirable attribute of some cymophane is what is called the “milk and honey” effect. Sometimes these other stones are called cats eye but they are properly described differently than in the actual real cat’s eye which is always called (or should be) cat’s-eye chrysoberyl. Some others stones such as alexandrite, tourmaline and moonstone may occasionally exhibit something that appears to be the chatoyancy effect but the only stone in which it is produced in this particular way is cymophane. There is a legend in some Eastern countries that if one brings one of these stones out into the light of a full moon on a clear night, the light reflected by the stone could show you the way to a hidden treasure. As either the stone or the light source is moved toward one side or the other this narrow white stripe appears to follow it.Ī stone that is cut as a cabochon oval particularly resembles an actual cats eye with the iris narrowing in response to the ambient light in which the animal finds itself. When light hits these inclusions it creates a bright, visually almost white, stripe that appears and runs perpendicular to these internal inclusions. This reflectance effect occurs because of very fine fibrous inclusions within the cymophane stone. The popular name of this stone is taken from the optical effect known as chatoyancy, a term derived from two French words: “chat” meaning cat and “oeil” meaning eye. The usual size seen in the trade is somewhere between 0.10 carat and 3 carats, although there is an 85 carat stone on display in the Museum of Natural History in New York. There are also stones as pale as yellow and as dark as brown. The color range of cymophane runs from a golden honey color to a mint green, but the highest value colors are a rich gold. It is rated between 8 and 8.5 on the Mohs scale of hardness which means it can take a fairly high amount of abuse compared to some other stones often used in jewelry. Although cymophane is often found in Brazil, Africa, and Madagascar the largest and best examples come from Sri Lanka. It is formed of beryllium aluminum oxide and appears as a relatively small percentage of the chrysoberyl stones. The only stone that can be properly described as being a cat’s eye is the variety of chrysoberyl known as cat’s-eye cymophane. The third family of stones exhibit asterism, an effect that produces a star on the surface. Two of them, popularly known as cat’s eye and tigers eye, are well known. The final instalment in my series on jewels that play with light examines three different gems that, while they do not change color, have a unique internal structure that allows light to produce interesting optical effects.
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