Okay, it's sparkley. Now what?
February 16, 2006 10:54 PM   Subscribe

What should I do with an 18 carat synthetic diamond?

So I got this huge synthetic diamond, mostly out of curiosity. Actually I don't even know if it's a real diamond, but it does scratch glass. So that means it is one, right?

Anyway, now that I know what it's like, what should I do with it? It's so absurdly large no one would belive it was non-synthetic, I would think, but who knows.

Here are some pictures:
posted by delmoi to Grab Bag (29 answers total)
Response by poster: Oh, and should I get it appraised? how much would this be worth if it were natural?
posted by delmoi at 10:56 PM on February 16, 2006

So that means it is one, right?

It could just be a quartz crystal (which is what it looks like to me). If it were natural, with good color, clarity, etc, it could be in the seven figures. Just take it to a rockshop -- they'll tell you what it is in seconds.
posted by frogan at 11:58 PM on February 16, 2006

Glass scratches glass and synthetic means not real.
posted by Cosine at 11:59 PM on February 16, 2006

According to this calaculator, 15.99 carat flawless (color and clarity) diamon is worth close to $1,200,000.
posted by falconred at 12:02 AM on February 17, 2006

Best answer: I half think this is a goof, but I'll go with it. At 18 carats, you almost certainly have a cubic zirconia and not a synthetic diamond. Even synthetic gem diamonds are pricey, the price point I saw a reference to was 70% of the cost of a natural diamond.

You've probably heard about the 4 C's of diamonds: cut, color, clarity, and carat weight. Each category significantly affects the value of a diamond. Even so, 18 carats is plain old huge and the cheapest would run into the hundreds of thousands of dollars. I found one 18 carat diamond at Blue Nile. It sells for $600,000 and it isn't a terribly good color or clarity for a nice diamond.

As far as the only diamonds cutting glass myth, it simply isn't true. Glass has a hardness of 5-6 on the Mohs Hardness Scale. Quartz has a hardness of 7 and will cut glass with effort. Cubic zirconia is 8.5 and will cut glass much more easily. Diamond is, of course, a 10.

The cubic zirconia Wiki link listed above discusses several ways to distinguish a cubic zirconia from a diamond. Looks like the easiest way is to heat one end of it and see how well the heat conducts to the other end. Diamond is a great heat conductor, better than copper, while cubic zirconia is an insulator. Or instead, you could buy that 18 carat diamond from Blue Nile and measure it compared to your presumed imitation. Since diamond is only 60% of the density of cubic zirconia, the 18 carat diamond should be much larger.

But any jeweler could probably tell you in seconds what you have.
posted by mdevore at 12:17 AM on February 17, 2006

I've heard retail prices of around $4000/carat for synthetic diamonds. However, I don't think anyone is producing 18 carat synthetics. Try rubbing it with wet/dry sandpaper*. If it is damaged, then it probably isn't a diamond.

*Ryanrs is not liable for any diamonds damaged by this test—natural, synthetic, or zirconia.
posted by ryanrs at 12:26 AM on February 17, 2006

looks like CZ to me, after looking at pages of pictures of CZ, diamonds, and quartz (which doesn't seem to be cut into this form, usually, but IANAGemologist). Diamonds seem to have whiter light speckles around them, while CZ tends to be more flashy/rainbow-y. Yours looks pretty rainbow-y. Sorry for the unscientific language, but this is an absolutely unexpert opinion. If you want a real judgement take it to a jeweler, or use mdevore's conductivity test.
posted by MadamM at 12:56 AM on February 17, 2006

You put it on a ring, then wear it.

You go skiing, and get on a T-Bar with a stunningly attractive girl. (May have to wait aside for a bit here)

Half way up the ride you remove your glove and say; "Gosh this thing keeps catching on my glove!" whilst waving your appropriate hand around ensuring maximum sparklability.


A) Replace your glove and let nature take its' course

B) Remove ring and throw to the side and let nature take its' course

Either way, you're onto a potential winner as the best chat up going!
posted by DrtyBlvd at 6:07 AM on February 17, 2006 [1 favorite]

There are quite a few clear stones that are quite brilliant when facet-cut. It could actually be worth something. Where'd you find it/how much did you pay?
posted by desuetude at 6:12 AM on February 17, 2006

I surmised from a Wired article about Gemesis that the largest jewelry quality synthetic diamonds are typically cut to 3 carats. Other cursory Google searching revealed similar information.
posted by xyzzy at 6:13 AM on February 17, 2006

Take it to a jewelry store and make sure that a graduate gemologist looks at it. A look under the miscroscope will tell whether it's diamond or not, but further testing (refractive index etc.) would be needed to definitively tell its identity. You may have to pay for this.

If it's not "synthetic diamond" - i.e. man-made diamond, then it is most probably either a diamond simulant such as CZ or a clear stone such as quartz. My money would be on quartz, since it's common to find large clear specimens such as that.
posted by Flakypastry at 6:21 AM on February 17, 2006

I will give you $50 for it, right now.
email is in profile.
posted by Baby_Balrog at 6:25 AM on February 17, 2006

My understanding is that the refractive index of diamond is so great that you can't see through it. From the picture, I think we can see the coin quite clearly through the stone.
posted by Leon at 7:14 AM on February 17, 2006

Moissanite, which is a type of silicon carbide and is nearly as hard as diamond (9.25 on Mohs), is now popular as a diamond simulant as well, but I would also bet on CZ. As several people have noted above, synthetic diamond (which is not fake despite Cosine's assertion and deBeers' marketing) is still quite expensive and is very rare in large stones. (The exception is wafers of diamond which are grown for electronics by companies like Apollo Diamond, but those are generally quite thin and, well, wafer-shaped.)

If you don't have access to any lab equipment and don't want to go to a jeweler (even a marginally incompenent jeweler could tell Moissanite from CZ from diamond, and a half-decent one could probably do it by eye), then mdevore's thermal conductivity test is a good choice. Be sure to use a relatively low temperature heat source (read: not a blow torch, etc), though, in the (unlikely) event it is a real diamond. Contrary to popular opinion (and again, deBeers advertising), a diamond is NOT forever; it's thermodynamically only quasi-stable and turns to graphite in high heat.

In fact, there are plentiful stories of people who have discovered their "diamond" ring was actually CZ when it survived a house fire.
posted by JMOZ at 8:33 AM on February 17, 2006

I'm a gemologist. With all due respect to those that have posted their opinions in this thread, sight identification (that is, without the benefit of magnification and/or gemological testing) of a stone is impossible and, in fact, unethical by industry standards, If you indeed want to find out the identity of the stone (and then go on and insure it), you will have to take it to a qualified jeweler - and hopefully, a gemologist. Most insurance companies will not insure a stone of any value without an appraisal from a qualified professional.
posted by Flakypastry at 8:49 AM on February 17, 2006

Response by poster: Diamonds seem to have whiter light speckles around them, while CZ tends to be more flashy/rainbow-y.

Actually, it's not very rainbowy in normal light; I tried to take the most 'rainbowy' pictures I could, because I thought that they were supposed to be that way.

How do I get it appraised? Just take it to any jewelry store?

I'm not sure if I'd sell it for $50, whatever it is its kind of pretty.
posted by delmoi at 9:30 AM on February 17, 2006

"Actually I don't even know if it's a real diamond, but it does scratch glass. So that means it is one, right"

Means nothing, glass will scratch glass.

Leon writes "My understanding is that the refractive index of diamond is so great that you can't see through it."

Only if it is cut properly and then only when viewed from the top. A diamond that is cut too shallow or tall can be seen thru.
posted by Mitheral at 12:08 PM on February 17, 2006

Glass scratches glass and synthetic means not real.

It is most certainly real, there is a picture of it right there. It is probably man made, but that doesn't mean it's imaginary.
posted by Pollomacho at 1:35 PM on February 17, 2006

How do I get it appraised? Just take it to any jewelry store?

delmoi: Call around to your local jewelry stores. Ask if they have a graduate gemologist on staff that has access to the proper gemological equipment to make the right determination (microscope, refractometer,polaroscope). If they do, ask how much they charge for a stone ID, and if necessary, an appraisal. Depending upon where you are, that may cost as much as $100. A good gemologist will be able to look under the miscroscope and tell you if it's worth proceeding with testing at all. If they want to charge you a nominal fee to tell you that, okay, but I wouldn't pay more than $25 for that information. Good luck.
posted by Flakypastry at 1:45 PM on February 17, 2006

If it is a real diamond (seems highly unlikely- how did you come by an 18-carat anything, much less a diamond that would be worth 6-7 figures?), it is your Metafilterean duty to sell it immediately, and host the rippingest MeFi get-together in history with part of the proceeds.
posted by hincandenza at 1:58 PM on February 17, 2006

I opine that any professional who wants to charge you $25 simply to tell you whether you have a diamond or CZ is stiffing you. Indeed, I have gone to a certified appraiser about my mother-in-law's jewelry for her estate valuation. While we were standing there, the gem appraiser, for free, looked at each piece through her loupe and sorted them into two groups. One group of jewelry -- the depressingly small one -- represented what the appraiser said was possibly of sufficient worth to be appraised. It was then our decision on whether to continue and leave the jewelry for detailed appraisal. The fee to do this was around $90/piece.

Something to reflect upon: of the four sorted-out pieces, one appraised at a value less than just its appraisal fee and one appraised at twice the fee. Neither of the two remaining pieces bumped the estate's value to any serious degree.

C'mon, it's fairly likely you have a cubic zirconia. For $25, you could probably buy another 18 carat piece; you can get 10 carat CZ for less than $15. Of course, the gem appraiser might tell you it's not cubic zirconia, but another mineral of potential value (nice quartz or whatever), and then give you option to pay for that appraisal. That seems reasonable, and it's a good justification to visit a jeweler in case you have some true value in the rock. But attempting to charge a fee to tell you have a chunk of CZ is silly.
posted by mdevore at 2:42 PM on February 17, 2006

Second the request to know where this came from (and how you acquired it without some statement of what it is).
posted by Caviar at 3:21 PM on February 17, 2006

I'm _really_ hoping we get a follow up on this one.
posted by esch at 6:11 PM on February 17, 2006

Best answer: mdevore: But attempting to charge a fee to tell you have a chunk of CZ is silly.

Agreed, but it depends on the market. We rarely charge for such things, but in some locales, stores will charge for that service. We have no idea where the poster is located.

The sad reality is that there's lots of bad sight identification of stones out there, by "qualified professionals" with a hand-held loupe, often at those popular estate appraisal shows. I've been in the very uncomfortable position many times of having to tell an excited person that their family heirloom in fact contains a synthetic stone. Technology to produce synthetics (i.e. lab created chemically-identical stones) is getting cheaper and better, and it takes more time and expertise to recognize them.

Case in point: I had a customer that needed a diamond ring retipped - his wife had a 2-carat estate diamond ring that he had purchased from a local jeweler for $15k - "appraised" at $19k. (For the record, "estate" only means that the piece has been formerly owned - it could have been manufactured last week.)

Any time a large diamond comes in to be worked on, you have to exam it closely to see if applying high heat (i.e. heat from a torch) will compromise its integrity. Large stones are inherently unstable. Well, this stone had been fracture-filled - a relatively new diamond treatment that fills large inclusions in diamonds with a glass-like substance that has similar reflective properties of diamond, thus masking the inclusion and resulting in a better clarity grade. Exposing this stone to a torch would have caused the filler to leak out, thus making the large inclusion reemerge. Sellers of these stones, by law, are required to disclose the treatment to the buyer. But as the jewelry changes hands, the facts often get lost. Do I think that the jeweler that sold the piece intentionally failed to disclose the filling? I doubt it - I think that it was just a case of sloppy identification. So, the customer ended up with a $2500 nightmare rather than a $19k ring.

The bottom line is that quality gemological identification takes time, patience, and a LOT of experience. That's why it shouldn't be terrible to have to pay for expertise that you can trust.
posted by Flakypastry at 7:45 AM on February 18, 2006

Response by poster: Given the price I paid, I'm assuming this is probably CZ and won't get it appraised.
posted by delmoi at 3:28 PM on February 18, 2006

Response by poster: Well, what I'll do buy is buy a graduated cylinder and measure the volume. Since I already know it's 18 carat, I should be able to figure out the density.
posted by delmoi at 3:34 PM on February 18, 2006

Response by poster: If it was CZ, it should be about 0.63ml in volume, whereas a diamond would be about 1.02 ml in volume. That's a pretty big diffrence.
posted by delmoi at 3:44 PM on February 18, 2006

Response by poster: bleh, I'm not sure if I can find a graduated cylinder large enough to fit the thing in, but with a high enough resolution. I'll just assume it's CZ for now.
posted by delmoi at 3:54 PM on February 18, 2006

Best answer: Okay, I tried a 'poor mans thermal test'. Using the stove I was able to get one side of the stone pretty hot, while the other side stayed cool, so now I'm pretty sure its CZ. Ah well.
posted by delmoi at 5:45 PM on February 18, 2006

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