Chrysoberyl

  

The species name chrysoberyl is given to a transparent, faceted gemstone that does not show a colour change between daylight and artificial light (the chrysoberyl which shows a colour change is called alexandrite). The ideal colours of chrysoberyl are green and yellowish-green In addition, due to strong dichroism, one may see an attractive bi-coloured chrysoberyl occasionally. Hardness is 8.5 on the Moh’s scale. The high refractive index of the stose makes it very lively when properly cut and polished.

• Varieties:  Ordinary yellow-to-green chrysoberyl, cat's eye or cymophane, and alexandrite.
• Sources: Brazil, Madagascar, Myanmar, Pakistan, Russia, the United States and Zimbabwe.
• Toughness: Hardness of 8.5
• Precautions: Used for rough handling. General gemstone precautions are more than sufficient for this stone.
• Treatments: Chrysoberyl varieties do not respond well to heat treatment and are not routinely treated. When surface reaching fractures are present a fracture filling treatment can be performed to enhance the gem's appearance. This treatment can be detected using a microscope.
• History: The name chrysoberyl comes from the Greek words chrysos, meaning golden, and beryllos, which refers to its beryllium content. Chrysoberyl has been a prized stone for thousands of years in Asia, as it is believed to provide the wearer with protection from the evil eye.