Zirconium for use in jewelry. Zirconia is a component in some abrasives, such as grinding wheels and sandpaper. A small fraction of the zircon is converted to the metal, which finds various niche applications. Because of zirconium's excellent resistance to corrosion, it is often used as an alloying agent in materials that are exposed to aggressive environments, such as surgical appliances, light filaments, and watch cases. The high reactivity of zirconium with oxygen at high temperatures is exploited in some specialised applications such as explosive primers and as getters in vacuum tubes. The same property is (probably) the purpose of including
Synthetic diamond diamonds and diamond simulants. The revised guides were substantially contrary to what had been advocated in 2016 by De Beers. The new guidelines remove the word "natural" from the definition of "diamond", thus including lab-grown diamonds within the scope of the definition of "diamond". The revised guide further states that "If a marketer uses 'synthetic' to imply that a competitor's lab-grown diamond is not an actual diamond, ... this would be deceptive." The De Beers Lightbox brand entered the market starting in September 2018. De Beers had previously limited its synthetic diamond production to industrial applications. As of November 2018,