Chrysoberyl belongs to the spinel family in mineralogy. It is an oxide mineral containing beryllium and aluminum, and contains a small amount of trace elements such as iron, titanium and chromium. It belongs to the orthorhombic crystal system, the crystal is short column, plate or pseudo-hexagonal ring, with glass luster, transparent to translucent, hardness of 8.5, second only to diamond and corundum, and has excellent toughness. In the chemical composition of gold emerald, due to the different amount of iron elements, it has many colors such as honey yellow, wine yellow, yellow-green, gray-green, 等, but they all have a golden hue. There are two precious variants of golden emeralds, namely varieties with two peculiar optical effects: “cat’s eye” そして “color change”. The jewelry industry calls them “オパール” そして “allex” and lists golden emeralds as the world’s five most precious One of the gems actually refers to these two varieties.
“オパール” refers specifically to a golden emerald with a cat’s eye effect. This kind of gemstone contains many densely oriented inclusions within it. When illuminated by light, it produces a flashing band called “eyeliner”, which looks like a cat’s eye, so it is called “opal.” The opal is best in honey yellow or wine yellow, with the light band centered and upright as the top grade, and distinguished by the strength of the flash.
In nature, there are 20 kinds of gems with cat’s eye effect, such as quartz, アクアマリン, トルマリン, actinolite, apatite, feldspar, but their eyeliner is not as bright and clear as golden-green cat’s eye, so the jewelry industry has The golden emerald with cat’s eye effect is called “real cat’s eye” または “cat’s eye”, while other gems with cat’s eye effect cannot be called cat’s eye directly, and must be named with the original gemstone name in front of it. Such as “quartz cat’s eye”, “emerald cat’s eye”, “tourmaline cat’s eye”, they are rarely similar in appearance to real cat’s eye. 加えて, when observing the opal under a spotlight, you will sometimes see two interesting phenomena. One is to place the opal under the spotlight and form the correct angle, and you will see that the opal is half of the light showing its body. 色, and half of the backlight is milky white. The other is to place the opal under two condensing light sources. When you turn the gem, you will see that the eyeliner will open and close. When opened, there are clear areas separated, and when closed, a thin line is formed.