cahn: (Default)
[personal profile] cahn
So I'm going to talk about one of my major fandoms (that I don't usually talk about here), shiny things, because I can! (I started this post more than a month ago and it is high time to actually finish and post it.) In particular, I want to talk about diamond simulants and lab diamonds (although there's also very recently been some cool stuff about lab sapphires too). The funny thing is, I've never been a super fan of diamonds in general. I mean, I'm not going to say no to them! they are very shiny, and they have some cool dispersion (splits light into component colors, like a prism, so you get little rainbow flashes if it's cut well), and I love that they're super hard and come in octahedral crystals, but I have always been a colored stones kind of kid. But! In the last ten years there have been a ton of developments in this fandom relating to diamond simulants and lab diamonds, which I think is very neat.

First I want to define what I'm talking about.
Natural diamonds / earth-mined diamonds are diamonds that occur naturally in the Earth's crust and are mined from the ground.
Diamond simulants are not diamonds, but other substances that look enough like diamonds that they are used in jewelry that might otherwise use diamonds. I'll talk about cubic zirconia and moissanite as diamond simulants later on.
Synthetic diamonds / lab diamonds are chemically identical (*) to natural diamonds but are made in a lab.


Natural diamonds
For more than a century, the company De Beers has basically had a monopoly on diamonds (although I guess less so now). It has a huge stockpile that it sometimes has used to flood the market to drive out competitors and sometimes to withhold to drive up prices. Basically the supply of diamonds is controlled by De Beers. And so is the demand! De Beers has controlled a lot of discourse about diamonds. That thing about how engagement rings should be diamonds? That was a De Beers ad campaign. About how it should be some irritating multiple of salary? ALSO a De Beers ad campaign!

There is also a whole thing about blood diamonds / conflict diamonds and how many natural diamonds are involved in funding illegal/unethical activities. This doesn't seem like the majority of diamonds, but unless you happen to know the provenance of your diamond you don't know whether you have one of these. Lately (last 20 years or so) this has become a bigger deal and I believe they have been trying harder to document the provenance of diamonds so that this is less of a problem.

On a less existential level, I find diamonds rather boring because their classification is so regimented. When you buy one, there are the four C's that they are stringently graded on with very particular rubrics: carat, clarity, color, and cut (usually in that order, I think). Carat is weight, that makes sense; all precious stones depend heavily on that. Clarity is, well, how clear it is and how devoid of inclusions (non-carbon bits).

Color is a weird one: how colorless the diamond is, with the most colorless diamonds being prized and a slight tint of yellow/brown -- so slight I personally cannot tell the difference between more than two adjacent grades of diamonds, though of course a trained eye can -- making it drop in price. (Strongly yellow diamonds become "fancy colored" diamonds and then start commanding a premium (and become more interesting to me, lol, although the chance I would ever get a natural fancy yellow diamond is pretty miniscule; vivid fancy colored diamonds are quite expensive.) The weird thing is that they are graded FACE DOWN, which has always seemed nuts to me, because we don't ever look at the gemstone that way?? Whatever. (Colored stones are not generally graded on color in the same regimented way, because when you add in hue, "color" can become rather complex -- although color is the hugest thing about colored stones and very fine gradations in color can have a large effect on price -- but to the extent they are graded, they are graded face up! The way you would actually set and look at it!)

Cut is the most interesting one to me, as a good cut and polish can really make a difference, though here again the vast majority of diamonds are cut in ways that e.g. optimize brilliance, so... my understanding is that generally you just get as close to the "optimal" parameters as you can and call it a day. In fact, if you go someplace like Pricescope, you will see people post the various angles the stone is cut at and others will weigh in based on those. (Colored stones, in contrast, have other factors that affect the cut, like sometimes the color is different on different axes of the crystal, and sometimes you want to deepen the color so the cutter makes the cut deeper than "optimal" light return, and... it's just more interesting :) )

So when one buys a diamond, one figures out what particular grades one wants within one's budget and gets it. Now, as an aficionado of shiny things I'm not going to deny that some stones will have more presence than others, so to speak, and I totally believe that the people who post on Pricescope love their diamonds. I just find it all very commodified.


Cubic zirconia
For many years, if you wanted something that looked like a diamond but was cheap, the go-to was cubic zirconia (cz), which looks pretty similar to diamond, comes in lots of fun colors if you like that sort of thing (exactly zero people will be surprised that I do), and is dirt cheap. For a while it was hard to get well-cut cz, which has led to it having a poor reputation for looking fake (because badly-cut cz looks awful), but starting in the early 2000's it was possible to get well-cut cz. When D and I got engaged around that time, I could not find a sapphire that I was happy with (which would have been my preference), and there was some family pressure to get a diamond, and for the above reasons I didn't want a diamond, so my official engagement ring contains a (well-cut) cz. (No, my family doesn't know.)

The rise of moissanite
There is also this thing called moissanite, which is silicon carbide and occurs naturally in meteors though not in enough quantity to make jewelry. It was discovered more than a hundred years ago, but just in the last quarter-century or so (wikipedia says 1998) the company Charles and Colvard figured out how to synthesize it and sell it as a diamond simulant. Moissanite is actually really cool -- it's doubly refractive (which can be a plus or minus for gemstones depending on the cut -- makes some cuts look blurry but adds interest to others) and has more fire/dispersion than diamond, and while not as hard as diamond is harder than sapphire! But historically, moissanite was pretty expensive compared to cz -- you could buy a badly-cut carat (*) cz for dollars at the most and a well-cut cz for a hundred dollars dropping to a few dollars during the mid-to-late 2000's (+), and moissanite at that time would have been, as I remember, maybe a thousand dollars? Still rather better than a diamond, which was more like a few thousand dollars. Moissanite's price came down a bit over the years, but not substantially. It also could tend to have a green tint.

...Until 2018, when the moissanite patents expired and China and India started making a ton and the cost dropped like... like a stone, and the quality went up too. Now, in 2025/2026, a GH ("second-tier" color, very respectable for a natural diamond, looks clear/untinted to someone who is not an expert) 1-carat moissanite stone from China on Aliexpress or the like is a few dollars! (Note: in general I do not particularly recommend buying from Aliexpress or the like unless you know what you're doing and in particular what stores are reasonable ones, but moissanite is pretty safe because it's so cheap.)


The rise of lab diamonds
I started hearing about lab diamonds in... probably the late 2000s (when I was spending the most time looking around at shiny things). It took a while for lab diamonds to be commercially viable at all, because early lab diamonds (made by a high pressure high temperature (HPHT) method like natural diamonds) were small and yellowish-brown. By the time I was hearing about them, the HPHT technology was getting reasonable at size and color, and lab diamonds were also being made by another mechanism, Chemical Vapor Deposition (CVD), whereby carbon atoms are deposited around a diamond seed, which was cheaper and faster but the diamonds weren't as good. At that point, it was so hard to make them that the price of lab diamonds was pretty similar to that of natural diamonds, maybe very slightly cheaper, so it was more of a novelty than anything else. Ten years ago, a 1 ct diamond (with good color/clarity/cut) was around $5-6k for both natural and lab diamonds.

But improvements kept being made, both in the quality of lab diamonds and in producing them more cheaply. (For example, now CVD diamonds go through a round of HPHT post-processing, so to speak, to improve color and clarity.) China and India started really getting into it. Seems like it was a pretty steady improvement process, and prices have kept dropping and dropping -- this article shows a chart, for instance, of prices from 2016 to 2023. And I looked up 1-ct lab diamonds today [this was written Dec 2025] and Calavera (a well-regarded online shopfront) is selling a 1 ct lab for around $400. You can easily get a 1 ct diamond for four hundred dollars in 2025. (***) And I have no reason to believe lab diamonds won't continue to go down in price. (That is, if tariffs don't ruin it all.)

And it turns out that (which is more interesting to me!) you can also make colored lab diamonds pretty easily, with fancy yellow and pink and blue colors that would be extraordinarily expensive naturally.

I think this is all great! The more shiny options, and the more cheap and accessible they are, the better! Down with monopoly! Shinies for all! (Although nowadays, gold and even silver are so sky-high that those prices are now to a large extent driving the cost of jewelry. Still -- I'd rather be paying for gold than for diamonds. At least gold is honest about being a commodity!)



Lab ruby/sapphire
Then there is synthetic/lab corundum (ruby and sapphire) (****), which has been around at cheap prices (pennies to dollars) for decades. (There are different methods to produce it, one of which is extremely cheap and the others of which are somewhat more expensive.) And spinel, which is a natural stone that is a little less common commercially but is also very beautiful -- there are some really electric and gorgeous red/pink and blue shades of spinel that are naturally very rare and pricey, but can be grown in the lab very cheaply. (I am a super big fan, unsurprisingly! Lab spinel is awesome!) For a number of years it was very easy to get lab ruby/sapphire/spinel but hard to get it cut well unless you got someone to hand cut it for you *raises hand, because I am crazy and was more crazy in those days* and any gemstone looks pretty crappy if cut poorly, so the lab material had an undeservedly poor reputation. But recently the memo seems to have gone out that hey, it looks a lot better if you cut it decently! I've been seeing a lot better cut stuff in the last few years or so. It's not the same as a precision cut by a lapidarist, which is still of course the gold standard, but it's not the horribly awful cuts with poor polish that I was seeing twenty years ago.

The remaining problem with lab sapphire is that there are a few shades that are commonly grown, and if you want something different that isn't one of those shades, you are out of luck. (This is also the case for lab spinel, but in practice everyone, including me, just wants the electric red/pink and blue colors :) ) China, in its quest to dominate the costume jewelry world, is producing more lab sapphire colors these days (and good for them!), but there's also something else neat going on.

Pure corundum (aluminum oxide) is colorless (and in fact much is grown that way for industrial use); various impurities introduced into the crystal are what give it color. (Chromium makes rubies red, and titanium and iron make sapphire blue.) There is a rock star in the faceting-and-synthetic-gems world, Arya Akhavan, who has been noodling around with this stuff for years, and he recently just put together a kickstarter that's doing some careful modeling and laboratory synthesis of various different kinds of coloring agents for lab sapphires. (I didn't think to link to it as it was still going on, but late pledges are still possible.) It got funded at more than 450% of their original goal. I'm so excited to see what comes out of this!



Photos
Synthetic and simulant diamonds
Here is a pic comparing three stones I own. The ring is my engagement ring, and is a well-cut CZ. The silver necklace is moissanite, while the gold necklace is lab diamond. They all look pretty similar :)

On my ring finger is a lab sapphire; on my index finger is a lab spinel (with cz side stones). Both in sterling silver. I couldn't quite capture either of the blues with the phone camera (the sapphire has a slight purple cast that is not at all evident in the picture, and the spinel is a bit darker and more saturated than it appears), but it gives you a general idea.


(*) There are little things that can be different, so generally speaking lab diamonds can be distinguished from natural diamonds by a laboratory, but basically they're both made of carbon and look identical, especially if you have the same "grades" in one as another.
(**) When I refer to "carat" in the context of diamond simulants in particular, I will always be referring to "size of an ideal-cut diamond," which is about 6.5mm in diameter for a round diamond. Simulants will have different weights than a carat, of course, but generally the industry refers to a "1 ct moissanite" as something that mimics a 1 ct diamond, even though the corresponding cubic zirconia will actually be heavier than a carat and the corresponding moissanite will be lighter! Of course, "carat" when referring to colored stones just directly means the weight of that stone.
(+) www.diamondcz.co.uk came along in 2004, importing well-cut cz from China, and took well-cut cz from a relatively expensive niche market to super cheap!
(***) And even less (<~$300/ct last I looked) if you're willing to deal with Chinese companies directly -- it turns out there are whole subreddits devoted to both moissanite and lab diamonds that have instructions on this.
(****) Also emerald and garnet! Lab emerald in particular is a very big thing, very popular these days among people who buy lab gems, though emerald is not as much my thing so I don't know as much about it. Lab garnet can also be doped to get a lot of different colors, which is fun. Emeralds can't be made by the super cheap processes so they've taken a couple of decades longer to get cheap enough to be popular, but nowadays you can easily get them cheaply.

Date: 2026-01-11 02:56 am (UTC)
seekingferret: Two warning signs one above the other. 1) Falling Rocks. 2) Falling Rocs. (Default)
From: [personal profile] seekingferret
At my last job I built an annealer for heat treating moissanite gems to improve their brilliance. At current job we are experimenting with using CVD diamond material (mostly polycrystalline, definitely not gem grade, but our supplier also makes gem grade, apparently they just tweak some process parameters) for a few applications. There seem to have been huge breakthroughs in laser cutting recently, one of our suppliers was describing a multi-axis CNC laser where they program both the gem orientation and the desired finished shape and it scans the rough material and figures out how to get the greatest yield and then cuts.

Date: 2026-01-11 05:19 am (UTC)
hamsterwoman: (mother necklace)
From: [personal profile] hamsterwoman
This is really interesting! I shared some tidbits with L as I was reading -- she had seen moissanite prices drop steeply some years ago, but didn't know why -- so now she does :)

I also find diamonds boring, but kind of like the extra shine of moissanite, and I like sapphires and emeralds a lot. I have a lab ruby ring, and had gotten L some lab emerald shinies. Didn't realize they make lab spinels -- that's neat!

Date: 2026-01-11 06:37 am (UTC)
sporky_rat: It's a rat!  With a spork!  It's ME! (Default)
From: [personal profile] sporky_rat

My engagement ring is a lab sapphire. It's ORANGE.

Date: 2026-01-11 12:15 pm (UTC)
scaramouche: Red Gibson guitar held by Sabrina Alouche (Default)
From: [personal profile] scaramouche
That is so interesting! I'm not much of a jewelry person myself but I also like looking at shiny things and that was fun to learn about the newer trends with cubic zirconia and lab diamonds.

Date: 2026-01-11 01:11 pm (UTC)
dolorosa_12: (cherry blossoms)
From: [personal profile] dolorosa_12
This was really interesting to read!

Date: 2026-01-11 02:12 pm (UTC)
luzula: a Luzula pilosa, or hairy wood-rush (Default)
From: [personal profile] luzula
Not my fandom, but still cool to read about! I do have a lovely necklace that I inherited from my grandmother which has a large cut stone in that classic diamond shape, which is the color of gray smoke. It's lovely, but I have no idea what kind of jewel it could be.

Date: 2026-01-11 03:44 pm (UTC)
mildred_of_midgard: (Default)
From: [personal profile] mildred_of_midgard
This was interesting in the sense that I always like when people do detailed write-ups on subjects they're passionate about!

Your diamond opinions made me laugh. I happen to think diamonds are boring, color is where it's at. :D I was also reminded of Anne Shirley dissing diamonds:

I think amethysts are just sweet. They are what I used to think diamonds were like. Long ago, before I had ever seen a diamond, I read about them and I tried to imagine what they would be like. I thought they would be lovely glimmering purple stones. When I saw a real diamond in a lady’s ring one day I was so disappointed I cried. Of course, it was very lovely but it wasn’t my idea of a diamond.

Okay, so maybe you can weigh in on something: I was told in December by a friend that her sister is a goldsmith and has a rant about how we shouldn't distinguish between precious and semiprecious stones. But, not being a goldsmith herself, she couldn't remember the rationale. I told her that when she visited her family at Christmas, she should get the rundown for me from her sister and tell me about it when she gets back. So I'm hoping she both remembered to ask and made good notes, and that I get the scoop in the next few weeks.

Do you have any thoughts on this subject, perchance?

Date: 2026-01-11 06:31 pm (UTC)
whimsyful: arang_1 (Default)
From: [personal profile] whimsyful
I've also never really been a huge fan of diamonds (sapphires all the way!) I really enjoy lab gems, mostly because I've found that what I care about the most is the cut, and you can get really interesting precision cuts for very affordable prices if you go for lab instead of natural. My engagement ring has a lab periwinkle sapphire cut by the lapidary Precision Gems and it's so so beautiful - I routinely get compliments on it from people who didn't realize a sapphire can sparkle that much. I also have another loose lab sapphire cut by mvmgems in her Jonquil design which I still need to get set into a ring or necklace.

Date: 2026-01-11 07:32 pm (UTC)
rachelmanija: (Default)
From: [personal profile] rachelmanija
That's so interesting. TBH my favorite is the spinel. It's just so bright!

I've never much cared for diamonds but I like a lot of semi-precious stones.

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