(IDEX Online) – Newly discovered “cryogenic” diamonds change color from gray to yellow at extremely low temperatures, say experts at the GIA lab.
They’re the opposite of “chameleon” diamonds, first discovered in 1866, which change color at very high temperatures.
Stephanie Persaud, senor analytic technician at the Gemological Institute of America (GIA) in New York, made the discovery by chilling a diamond to -320F/-196C, the temperature of liquid nitrogen. Click here to read full article. http://www.idexonline.com/FullArticle?Id=47064