Synthetic diamonds are made in a lab and cost less than mined diamonds. However, are they of the same quality and what other considerations should we make before purchase?
Let’s add some facts to the comments below so the truth can shine through. We’ll award some BS Buster badges to the best answers!
There is no such thing as a “synthetic diamond”?
Whether it is dug from the ground or industrially made both have exactly the same properties and chemical structure.
I guess the same discussion applies to synthetic cotton. Eg polyester, rayon etc. They are all synthetic fibres and used to produce synthetic textiles. They are not the identically the same physically or chemically as cotton.
@BrendanMays, do you mean to ask are industrially made diamonds as good as diamonds formed naturally in the earths crust? Or are we comparing cubic zirconia and rhinestones with the Crown Jewels?
DeBeers and the US Govt can’t agree on what to call them.
In July 2018, the U.S. Federal Trade Commission approved a substantial revision to its Jewelry Guides, with changes that impose new rules on how the trade can describe diamonds and diamond simulants.[115] The revised guides were substantially contrary to what had been advocated in 2016 by De Beers.[114][116][117] 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.”[118][116]
Ref
That’s the one 
Thanks for sharing that info regarding the semantics.
On your first point, I thought that experts can distinguish between the stone made in a lab and deep in the earth. If that is so they do not have exactly the same properties.
On your second, I am mystified. You are comparing examples of synthetics to natural products that they are not chemically identical to, which is the converse of your first claim. So how do we have the same discussion about them?
It looks to me that De Beers have a vested interest in trying to control the name “diamond” to prevent their business model from being challenged. They would like very much to control the world supply of diamonds - all diamonds. One way to do that is to try to stop the stones that they cannot control, the ones made in a lab, from being called a diamond.
As for the broader question of are lab-made stones as good as geologically made ones the answer depends on your criteria.
If by “good” you mean the lab made are as hard and sparkly, so that they act for practical purposes (cutting and polishing and getting most girls to say yes) the same then they are as good. If you mean they will command ridiculous prices then no they are not. The reason being that price is based on rarity, large high quality natural diamonds are extremely rare. Synthetics will not be satisfactory for getting some girls to say yes because to them true love has lots of zeros after it.
The short answer is yes. They are probably better!
As @syncretic pointed our de Beers is vociferous in enforcing their control of the ‘diamond’ market, and maintaining the mystique of quality. ‘Diamonds’ are a fashion item that is kept in demand by manipulating the supply, and by manufacturing demand, that is advertising which creates emotional responses.
Most diamonds sold are not top grade based on the cut, clarity, carats, shape, and fluorescence. Most have some flaws, and are not pure in colour. The synthetics on the other hand are much more consistent in quality having gone through a standardised manufacturing process.
If diamonds were intrinsically valuable, why are the old cuts worth less? After all, the diamond itself hasn’t aged. (Hint: it’s all about fashion, because the old cuts refract just as well as the new ones.)
I am not sure about fluorescence, but otherwise if you ignore all the hype and look at the stones dispassionately, the manufactured stones are as good if not better than the natural stone in all except on the Moh’s Scale of Hardness, where they come in a close second. And they are seriously cheaper.
So yes they are as good.
It also depends on the basis. The synthetic will win on a drill bit, but when it comes to jewellery value the bespoke real one will always prevail. If it was objective why would they have any value as one cannot eat or drink them, and having enough to wear as clothing, well.
The diamond market is all De Beers as much as the eyeglass world is Luxotica. It is all about marketing, manufacturing (or mining), and manipulation, and De Beers will not leave any stone unturned for their dollar.
We already use the word “synthetic” to describe many industrially produced raw materials which are similar to natural products. Eg textiles, elastomers, insulation wool, lubricants, fuels etc.
Typically the invented or created materials mimic the natural product. They are at elemental level far from identical to the natural product. When compared to natural some synthetic materials may have enhanced properties. Synthetic motor oils are one such product, gortex cloth and Velcro are other examples.
Considering the use of “synthetic” to represent any manufactured material/product.
Manufactured (laboratory) diamonds are a special instance where they are identical chemically, atomically and physically to the originals. This accepts that there is always some variation in impurity present whether diamonds are naturally formed or manufactured. The impurities can colour diamond, and reveal minor measurable variances between naturally formed and manufactured.
Accepted, the point needed clarification.
Relegating my ignorance of diamond naming to Wikipedia:
In July 2018, the U.S. Federal Trade Commission approved a substantial revision to its Jewelry Guides, with changes that impose new rules on how the trade can describe diamonds and diamond simulants.[115] The revised guides were substantially contrary to what had been advocated in 2016 by De Beers.[114][116][117] 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.”
On this basis the difference between diamonds dug from the ground and manufactured in a processing plant, (laboratory) has been all but extinguished.
So which one is cheaper, and can the eye tell what the heart does not know?
More likely the manufactured diamonds will be flawless and more consistent in colour, 5C’s?
It’s possible that in the near future as manufacturing improves, and costs come down further, most “naturally formed” dug diamonds will be devalued accordingly. In this instance only the one of a kind over sized specialty stones with a unique history attached may hold their value.
As an investment neither option of “synthetic” or “naturally occurring” appeals.
For drilling concrete both work the same.
For future applications in the electronics and computing sphere, the manufactured product is likely to be the only option.
Share this at your own peril with your partner if like mine they cherish attachment to the rocks on the ring fingers. 
Thanks for the discussion here all. The discussion covers a lot of considerations about synthetic diamonds 
that will hopefully help anyone considering their purchase options.
This topic would not have been started for ‘a friend’ contemplating a purchase, would it? 
Being married I’ve already made one sizeable diamond purchase. Synthetic wasn’t really an option but personally I would be happy to buy them in the future.
… not speaking for you @BrendanMays, but I reckon origami folded diamonds are sufficient for many marriages these days
I’m waiting for cryptocurrency rings and other digital talismans to become de rigueur.
Love the paperwork. No pen or forms in sight.
Really, do you jest? 
Paper is only the first wedding anniversary (US traditionally).
Although the modern American tradition appears to have updated that to a far more expensive and equally useful item, the “clock”!
Surely some marriages make it to at least one of the following cloth (2nd) or leather (3rd)? China and Crystal respectively which may come in handy if you need to make a point about not needing to get to the fourth - electrical appliances in modern terms!
You appear to need to reach 60 years of ‘forgetfulness’ (which may be apt for some of us in our twilight years) to genuinely achieve diamond/s.
Synthetic or real, will it really matter by then?
I was thinking that would be the second time for clear rocks - the first being the engagement ring …
I reckon a healthy appetite for leather might keep the spark?
We may be digressing …
I would too, but in my case (and perhaps yours?) it could end in a lengthy couch test. Of course when the couch test gets published it could pay for a real one.
While not digital, ‘blockchain rings’ exist. I suppose one could argue they are linked to the cryptocurrencies…?I think one may need to speculate with the crypocurrencies to be able to afford one. Here is one example (noting that they are not to my taste and would be a nightmare to keep clean)…
And so the couch test begins
