While not a GG, I have some experience.
The term for these would be lab grown diamonds. They are C-C-C-C-C... They will not have the value of natural diamonds and history shows that they would not impact real diamond prices. There are lab created rubies, sapphires, emeralds, etc., and they still are in demand and have not suffered because of man-made material. They do have a problem with identifying which is natural vs not. With many lab or synthetic materials, a standard jeweler's loupe is not enough. A Graduate Gemologist would not use a loupe to identify a precious stone. The diamond tester would show that it is carbon and diamond. It would next go to a filter and then a microscope. The microscope will show the lab material. Nature abhors perfection. Natural materials have all sorts of inclusions and imperfections that show under extreme magnification. For example, lab materials do not have things like other materials growing in the crystals. Rubies commonly have rutile crystals and growth plates as well as bubbles, color zoning, etc. The microscope can even reveal treatments (heat and diffusion can be used to change the color of a sapphire to a ruby). They also do stuff like filling cracks with glass to make the ruby look better. Glass filled material is cheap, but a real, untreated, clean ruby is extremely valuable.
On natural diamonds, the Cartel and the Russians have them stockpiled. It is rumoured that Russia has a very large stockpile of diamonds, and if released, could destroy the market (and even make lab material not worth the effort possibly). Diamonds are far more common than good sapphires, rubies, emeralds, and a few more things.
Factoid, diamonds are cut with diamonds from Australia. There is a mine (near Darwin?) in Australia that produces diamonds that are much harder than those in jewelry. Those are used on the diamond cutter laps to cut jewelry diamonds.
CZ, cubic zirconia, is zirconium oxide. 8-8.5 Moh and a refractive index almost at the diamond level. RI really comes into effect when calculatiing the critical angle of the pavilion (bottom) and crown (top) of the stone. For example, quartz has a RI of 1.54. Using a trig formula, the critical angle is calculated to just under 41 degrees. If ever facet is greater than 41 degrees, light will reflect back instead of passing through the stone. You have seen this effect looking into an aquarium as the sides reflect, but you can see through the back. More here if you wish to read about RI
http://www.rockhounds.com/rockshop/gem_designs/refractive_index/index.shtml CZ has a higher dispersion than diamond, so can out sparkle it. Dispersion is where the fire comes from.
For the record, I cut my avatar. That is a 7+ caret Jackson Crossroads Amethyst with 161 facets (Portuguese cut). JXR Amethyst comes from east of Athens, GA and is considered the finest amethyst. The material shows both blue and red flashes depending on the light. Some JXR material is valued at $100/ct, which is high if you consider it is quartz. That stone is probably worth $500-1000.
Edit - forgot... I cut a lot of CZ because it looks good and is cheap to experiment with. I can get it for 1-2 cents per caret on ebay from Jewel Electronics. Another company in NY makes a wide range of lab materials if you want to see what you can get. That is Morion Company and run it together with .com for their site IIRC.
Facebook
Twitter