A diamond simulant gemstone sold by Diamond Nexus Laboratories (DNL) was ordered on 27 March 2012 and examined to see if it was different from ordinary and inexpensive cubic zirconia as claimed. They also claimed the gemstone was coated with corundum (aluminum oxide or sapphire) to give it more scratch and degradation resistance. In addition, DNL claimed the gemstone was polycrystalline.
We had ordered a gemstone in 2007 to see if it was different than yttrium-stabilized cubic zirconia as they claimed on their website at that time, but found then that it was virtually identical to known Signity yttrium-stabilized cubic zirconia. The DNL website in March 2012 displayed laboratory reports on gemstones they said they had developed with a corundum surface coating. This is the product we purchased and examined. However, we found that the March 2012 product was still just yttrium-stabilized cubic zirconia without a surface coating of corundum. It was clearly also not polycrystalline, but was instead a single crystal, as one would expect a diamond simulant gemstone to be.