Diamond Coated CZ Engagement Ring

Posted by on Tuesday, November 4, 2014 · 1 Comment 

Last week I was presented with a lovely engagement ring to appraise. The ring was constructed of platinum. The young couple represented the round center stone as a diamond, and it was surrounded by a typical round diamond halo. There were two additional small round diamonds, each wrapped in a platinum bezel, each positioned at the base and between the prongs.

As an appraiser, my job is always to first identify the gemstones. Following this I photograph, measure, estimate carat weights and then judge quality. Once this is completed, I research the value, prepare my report and mail it to my client within a day.

The center round stone was incredibly brilliant and quite colorless. Internally, there were a few very tiny crystals off to the side and down deep. I was bothered however by the base of the stone, the bottom facets. They did not appear to reflect light in the same way as the facets on top. Perhaps the base of this diamond was poorly cut, allowing more light to leak out the sides. I took another look at the top of the stone in my microscope. The lines forming the facets were precise, narrow and sharp, exactly as they should be in a natural diamond. I then tested the stone using a typical diamond probe, a tool most jewelers have to test the heat and electrical conductivity of the stone. Sure enough, the result was diamond. I was still bothered.

I asked permission of my clients to remove the stone while they watched. After doing this, I turned the stone over and examined the facet lines on the base. They were slightly thicker and more rounded than the lines atop. I then tested the base with my probe, and it turned out not to be diamond.

Several decades ago, experiments were conducted with diamond dust to coat the surface of a gemstone using the chemical vapor deposition method. This has become one of the methods used today to grow synthetic diamond in a laboratory. The stone I had been examining turned out to be a round colorless cubic zirconia with a microscopic layer of diamond adhering to the surface, creating both the appearance and the features of diamond, and a lovely imitation gemstone it its own right.

I reset the stone and returned the ring to my clients while they continued to observe the process.

In conclusion, diamond coated CZ can easily be mis-identified by good jewelers as a diamond. The public should be cautious when they purchase stones outside the normal paths diamonds take from the earth to the consumer, and jewelers should be cautious when they purchase gemstones from all sources. Sometimes what appears to be a remarkable bargain turns out not so special. Yes, it can go the other way also, and those appraisal appointments always give me a great deal of pleasure when I inform the clients of both their luck and good judgment with their purchase.


One Response to “Diamond Coated CZ Engagement Ring”
  1. Larry Wells says:

    Mr. Tom Tivol,

    I found your diamond coated CZ article to be educational and intriguing. I will remember this lesson.

    Thank you for sharing.

    Larry Wells

Please Leave a Comment

  • Recent Tweets