Zirconium dioxide for aesthetic reasons, or of 2) strong, extremely durable dental prostheses constructed entirely from monolithic zirconia, with limited but constantly improving aesthetics. Zirconia stabilized with yttria (yttrium oxide), known as yttria-stabilized zirconia, can be used as a strong base material in some full ceramic crown restorations. Transformation toughened zirconia is used to make ceramic knives. Because of the hardness, ceramic-edged cutlery stays sharp longer than steel edged products. Due to its infusibility and brilliant luminosity when incandescent, it was used as an ingredient of sticks for limelight. Zirconia has been proposed to electrolyze carbon monoxide and oxygen from the atmosphere
Diamonds as an investment the De Beers cartel in 2001, the industry is now more fragmented resulting in a higher percentage of diamond sales taking place in the form of auctions and other forms of open-market sales. Since the 1950s, techniques can produce diamonds of essentially any desired chemistry or size. and with fewer flaws than natural diamonds have. Although some manufacturers do label their synthetic diamonds with serial numbers there is no guarantee that a given diamond is not man made, although sometimes an unnatural chemical composition or pattern of flaws may suggest a diamond is synthetic. It is much cheaper to produce