Since Robert Crowningshield's discovery in the late 1950s that diamonds that have been artificially colored by irradiation and subsequent annealing could be identified by their characteristic ...

11月生まれの方は、2つの美しい誕生石、トパーズとシトリンからお好きなものを選ぶことができます。トパーズには虹のように様々な色があります。そしてシトリンには魅力的な黄色や ...

Figure 1. This 4.89 ct colorless synthetic sapphire was presented as a sapphire. Photo by Meenakshi Chauhan. A 4.89 ct colorless oval mixed-cut specimen was submitted as a sapphire to the Gem Testing ...