a girl’s best friend

Bridezillajenluc One of the first things that a newly betrothed woman must do is get her shiny engagement ring properly sized, I discovered last November. I'd never been one to wear rings of any sort, but really, how hard could it be? I figured I'd just find a local jeweler to do the job, since I believe in supporting small neighborhood businesses whenever possible. Alas, it turns out the road to re-sizing is fraught with peril if one lacks a knowledgeable guide. And I picked the wrong local jeweler.

He seemed competent and nice enough when I inquired about sizing the ring, and the price was reasonable, so I dropped off my ring and returned a week later to pick it up. The size was correct, but the color seemed a bit off, and the metal (white gold) had lost its sheen. When I checked the back of the ring, I noticed that the jeweler had pretty much just cut away the excess metal and soldered it back together with a new plain white gold double band — which might have been less noticeable if the original bands weren't carved with a decorative motif that was absent from the new ones. Examining the ring more closely under better light once I got home, I noticed that the new metal didn't even match the original ring in color.

I'll spare you the account of my ugly confrontation the next day with said local jeweler, when I complained about his shoddy work, except to say that he tried the oldest argument in the book: "You know nothing about gold! How dare you come in here and complain about my work?" That's not a very good argument to present to a woman who writes about science for a living, with a particular interest in materials physics, because I actually do know a little something about gold — certainly more than his average customer. His point was that he'd had to use gold (i.e., a compatible metal) rather than something closer in color, like silver, to solder the ring back together and therefore wasn't able to match the color. Also, the heat from the soldering reacted with the chemicals in the air and dulled the original finish, which he claimed was beyond his power to prevent. I countered by arguing that this wasn't the point of contention: my objection was to the finish work — more precisely, the complete lack thereof.

A brief recap of the various types of gold used in jewelry might be in order here, especially for other newly engaged persons, because what happened to me is not uncommon. Yellow gold will always be the, er, "gold standard," particularly the 24-carat variety, which has a higher purity than, say, 18 carat gold, which is made of 25% other metals, such as copper or zinc. But for things like engagement and wedding rings, white gold has become hugely popular in recent years. It's basically a gold alloy containing at least one white metal to "bleach" the pure gold and lighten the color — usually palladium, nickel, and occasionally silver; cheaper alloys may also contain copper, compromising the color a bit more. Most plain rings (simple wedding bands, for example) use a nickel alloy, which is both hard and strong, while the more malleable palladium variety is favored when gemstones are involved. The quality can range from 9 carats to 21 carats, but the most common is 18 carat white gold, made by mixing 75% gold with 25% other metals.

However, most people don't realize that white gold jewelry is often electro-plated with rhodium to improve the color and make it more shiny and silvery, and therefore more appealing to the customer. Eventually the coating starts to wear off and the ring becomes more off-white and dull in appearance, but a good rhodium plating should last at least three years before this happens. Exposure to harsh household chemicals can exacerbate the wear and tear, and so can soldering — which is what happened in my case. That's what I meant by the lack of finish work. I could have forgiven the sloppy soldering job, since  that's just the back of the ring, which doesn't show. But to not bother with re-applying a new rhodium coating after the sizing demonstrates –among other things — a lack of thoroughness, not to mention pride in one's handiwork. I cut my losses and took the ring to a more reputable jeweler, who re-coated it so it looked good as new.

The small diamonds in my ring weren't affected at all by the sizing fiasco, diamonds being among the hardest naturally occurring substances known to man.  Jen-Luc did a bit of nosing around the Internets and found that "diamond" derives from the ancient Greek adamas, meaning "invincible" (thank you, Wikipedia). The online consensus is that diamonds were first mined in India; there are references to the gems in a Sanskrit text, the Arthashastra, circa 296 BC, as well as a Buddhist text known as the Anguttara Nikaya. They soon became associated with divinity, which is why they were used to decorate religious icons.

Diamonds were also popular in ancient Greek, Roman and Chinese culture. The Greeks poetically believed them to be tears from the gods, while the more pragmatic Romans believed they were splinters of fallen stars. Europe caught onto the fad rather late in the game, circa 1300 AD, in part because (a) Arabic traders restricted the flow of trade between Europe and India in earlier centuries, and (b) the Christianized Western culture was suspicious of the popularity of diamonds for decorating images of "false gods." (I'm sure we'll hear from commenters debating the relative merits of "BCE/CE" versus the traditional "BC/AD"  nomenclature, but I'm sticking with tradition in this instance.)

The modern world is even more pragmatic in its attitude towards diamonds than the ancient Romans; there's a huge global market for industrial grade diamonds (those deemed unsuitable in clarity or color for being cut into gemstones). Some 80% of mined diamonds find industrial applications: cutting, grinding, drilling and polishing, mostly. For instance, they're embedded in drill tips or saw blades, or ground into a fine powder for grinding and polishing applications. But these uses aren't unique to modern times. I happen to have a set of diamond-tip drill bits, thanks to having a father and a brother in construction, but similar tools were apparently used in Yemen as early as the 4th century BC. And in 2005, a team of US and Chinese archaeologists discovered four stone ceremonial burial axes dating back to the Liangzhu and Sanxingcun eras (4000 BC – 2500 BC), which they believe to have been polished using diamond powder.

Materials derive their various properties from molecular structure. In the case of diamonds, the hardness factor is due to the fact that each carbon atom is connected to four other atoms by strong covalent bonds. Chemists figured that much out in 1797, subsequently embarking on a centuries-long quest to make diamond out of baser forms of carbon (allotropes) or carbon compounds. Scientists didn't succeed until the 1950s; General Electric is usually credited with developing the first commercial process for synthesizing diamonds. Note that these are not "synthetic" gems, like cubic zirconia; they're actual diamonds, just made in a lab rather than being mined from volcanic pipes deep in the earth where high pressure and temperatures fosters the formation of crystals out of carbon deposits; the resulting gems eventually reach the surface with volcanic activity. The preferable term for the manmade gems is "cultured" diamonds. (As yet, there is no "acceptable" term for the practice of converting the carbonized remains of loved ones into "memorial diamonds," a la the LifeGem Company.)

GE has since invented another process for improving the color of certain natural diamonds — those that are somewhat brownish-tinged and therefore less expensive — by heating them in a special furnace.  Yes, diamonds come in many colors, the result of impurities (such as the presence of nitrogen) or structural defects; yellow and brown are the most common, although the famed Hope Diamond Hope was known as the "French blue," deriving its deep rich hue from the presence of boron. The GE process uses high heat (more than 1800 degrees Celsius) and pressure (between 50,000 to 70,000 atmospheres) to essentially redistribute the defects in the carbon lattice within the rest of the crystal. The resulting diamond resembles its pricier, colorless cousins once the process is completed.

That's just for mildly colored imperfect diamonds. Apparently so-called "fancy colored diamonds" are quite desirable if the color is intense and brilliant enough. (Jen-Luc is reminded of one of her favorite scenes in the musical Gigi, when the young title coquette-in-training is asked by her grandmother to identify various gemstones, and when presented with a yellow stone, guesses, "Um… topaz?" The grandmother, once the courtesan of minor kings, is horrified: "A topaz?!? In my jewels?" It turns out to be a rare yellow diamond.) Combining neutron or electron irradiation with annealing can turn more rare brownish natural diamonds into green-blue and orange-red shades, further increasing their value to the gem trade.

More recently, Gemesis Corporation has entered the commercial market for manufacturing atomically, structurally and chemically pure diamonds so well that it takes some pretty fancy lab equipment to distinguish the manmade stones from nature's handiwork. Similar high-temperature treatments with beryllium have been used to improve the qualities of rubies and sapphires — in fact, similar techniques were used even in ancient times, according to this article in Chemical and Engineering News. And certain Thai gem dealers have been chemically diffusing beryllium into low-quality sapphire and rubies by heating the stones in the presence of chrysoberyl, a mineral commonly mined along with pink sapphires in Madagascar. The result: gemstones of very rare colors.

So how do you know if your gemstone is "natural" or an artificially enhanced version (assuming you care about such things)? Unless you have access to high-tech spectroscopic instruments, you might just be out of luck. Even the Gemological Institute of America (GIA) has had to resort to expensive techniques like secondary ion ass spectrometry and laser ablation-inductively coupled mass spectrometry to quantify the various trace elements down to levels of parts-per-million.

In 2005, a team of German physicists at the University of Bayreuth created a material even harder than diamond by subjecting C-60 molecules to even more immense pressures — nearly 200,000 times atmospheric pressure — combined with very high heat (2500 degrees Kelvin). They call their new material "aggregated diamond nanorods," because unlike regular diamond, this carbon form is made of tiny interlocking diamond rods. If you've never heard of them, perhaps it's because the moniker just lacks the oomph of, say, buckyballs, or even carbon nanotubes. But once the manufacturing process is scaled up, aggregated diamond nanorods (ADNs for short) are expected to find loads of useful industrial applications, just like their other carbon siblings.

The German scientists were able to achieve the intense pressures to create ADNs thanks to 5000-tonne multianvil press. We had a nice conversation about diamond anvil cells here last fall — scientists routinely use such devices to squeeze materials between two opposing cone-shaped diamonds. They've also been used to simulate the extreme pressures existing in the centers of planets, creating new materials at the same time, such as metallic hydrogen and perovskite.

Speaking of intense pressures and temperatures, supernovae might well be the origin of carbonado diamonds,  so hard they can't even be polished or cut, making them useless as gemstones. They're composed of millions of small diamonds arranged in varying orientations. First discovered in Brazil by Portuguese explorers in the 16th century, carbonado diamonds were used to drill the rocks for the Panama Canal in 1905, and to polish Brazilian hardwood before shipping it off to Europe. They're only found in Brazil and the Central African Republic (although some geologists claim to have found it in Russia as well), which were once part of the same land mass.

Carbonado deposits are also much older than conventional diamond mines: 3.8 billion years or so, compared to 1 billion and 100 million years for diamond mines. That's what prompted scientists at the Florida International University — Stephen Haggerty and Jozsef Garai, along with Case Western Research University researchers Sandeep Rekhi and Mark Chance — to hypothesize that carbonados came from outer space, specifically, via a diamond-bearing asteroid that crashed to earth billions of years ago. That asteroid, in turn, was propelled into space as the result of a stellar supernova explosion.  The researchers used Brookhaven's infrared synchrotron radiation equipment to identify trace elements in carbonado, notably nitrogen and hydrogen. The presence of the latter in sufficiently high levels, per Haggerty, indicates the stuff came from interstellar space, which is especially rich in hydrogen.

Their online paper  on the subject appeared last December in Astrophysical Journal Letters. The NSF press release generated a huge amount of media coverage (there's an extensive list of links here), but the supernova-origin hypothesis is not without controversy: many diamond experts are skeptical. So is fellow blogger (and frequent commenter at the cocktail party) LabLemming, who asserted in a January post that the AJL paper "misrepresents the literature, fails to describe its samples and analyses well enough to allow an objective interpretation, and overstates the quality of the data." He also bemoans the utter lack of media coverage for a paper by Kagi et al. in American Mineralogist he deems to be "a contender for the best paper on the subject in the last five years."

LabLemming's specialty is, apparently, carbonado diamond, so we'll assume he knows his stuff from a technical standpoint. We can comment — albeit somewhat cynically — on the media angle: "it came from outer space" is just so much cooler than a standard dry materials paper, however careful and technically accurate the latter. Like it or not, spin sells. And "spinning" science doesn't necessarily make it "wrong." ("Ooh! Shiny!") Also, did Kagi et al. issue any sort of press release countering the hypothesis, thereby generating more media interest in their own work? (Does anybody even know Kagi's first name and research affiliation? This is vital information for journalists seeking to track down outside experts!) Even LabLemming has yet to post a detailed account of his critique of the Garai et al. paper, and reasons for preferring the Kagi et al. paper.

As a result, any journalist doing some preliminary Google research isn't likely to find much in the way of countering hypotheses. (If we all link to LabLemming's posts, maybe the Google ranking will skyrocket on that particular search. I try to do my part!) If they're experienced enough to have built up a network of scientific experts in various fields, they'll be okay, but many daily newspapers simply foist the science beat on Average Joe Reporter, who might not have those kinds of contacts.

I guess my point is that, while LabLemming's gripes are valid, it's very easy to grumble and point fingers at the mainstream media when it comes to science coverage — even more so when they muck up your favored research topic. But the problem is far more wide-ranging than mere ignorance/laziness on the part of reporters. Scientists need to be more media-savvy — where was the press release for the Kagi et al paper? Reporters at mainstream media outlets need to foster better ties with the research community and build up their own network of outside experts.

It would help if newspapers cared enough about science coverage to give reporters "beats" in specific subfields of science, but considering most no longer even have science sections — and what little science is reported tends to be health and nutrition related — that's purely wishful thinking. Still, sometimes the system works, and you end up with a well-written, accurate yet artistic article about a fascinating topic in science — as rare as a deep blue diamond, and just as valuable.

26 thoughts on “a girl’s best friend”

  1. Good article, but somewhere in the middle you say, “secondary ion ass spectrometry”. I’m not usually one to quibble with small typos, but that one was funny enough to point out.

  2. You mean there is no ion ass spectrometry?!? I read that and was about to go do some research, I’ve been looking at going back to school and that seemed like a promising new field of research…

  3. You mean there is no ion ass spectrometry?!? I read that and was about to go do some research, I’ve been looking at going back to school and that seemed like a promising new field of research…
    I must second Judah’s comment, this was a fun read.
    msd

  4. Since you are so wise in the way of gemstones, you may be able to help me out with something I’ve been wondering about. Are naturally occurring beryls ever green as a result of impurities other than chromium? And if so, are such beryls still considered emeralds?

  5. Gosh, I’m flattered, Jen. A bunch of scattered points:
    a. Carbonado is one of the most obscure minerals around, and generally doesn’t warrant a press release.
    b. Our reply is still being circulated between me and my co-authors, and then it should really be peer-reviewd before getting let loose on the internet.
    c. One of our complaints is that by publishing in an astronomy Journal, Garai et al. managed to sashay around the peer review system that probably would have been more effective had they stayed in the mineralogy literature.
    d. Kagi’s first name is Hiroyuki. The abstract (pdf) is here: http://www.minsocam.org/msa/AmMin/TOC/Abstracts/2007_Abstracts/Jan07_Abstracts/Kagi_p217_07.pdf
    The reason is is so good is that it finally sorts out the 3H/H3 luminescence puzzle. For those unfamiliar with this saga, here’s the short version:
    Previously, the Japanese reported all 504 nm lines as 3H, while the British reported them as H3. For those unfamiliar with diamond luminescence, the 3H defect and the H3 defect are two completely unrelated defects that both have a zero-phonon line at 504 nm. Even though the zro-phonon lines are indistinguishable, they have different higher order spectra and they anneal out at different temperatures. Kagi et al. showed that both can be found in carbonado, and described the processes that allow for one or the other to be seen. So suddenly, 15 years of confusing carbonado research (which is about 6 papers, due to the smallness of the field) suddenly makes sense.
    What I don’t understand is how to make that sound as compelling to non-spectrometrists as “Diamonds from outer space”.
    I hada bunch of points about gem diamonds, but my browser ate them.

  6. We talk about better science reporting, but I don’t know why anyone should expect the general news media to do any better reporting science than they do in all the other, less technical fields. Like politics, for example.

  7. So…the ring. Did you get it sorted out? I’m curious because it seemed like you left with a bad feeling for small independent craft jewellers. I’ve experienced the other end of the dilemma where a client says they just want a simple fix but then the aesthetics become an issue. You were right to support your local crafters and artists. I wish the communication could have been more productive. Why not have the original craftsman who made your ring originally re-size it and buy something that the 2nd jeweller makes as specialty. In the end, you have more and better jewelry, and have supported more artists.
    I’m makin’ carbonados my birth-stone, beauty being in the eye of the beholder.

  8. 1. There SHOULD be something called ion ass spectroscopy. I’m trying to find a tasteful way to come up with an amusing description of what such a technique might be, and failing… on the tasteful front. 🙂
    2. Jen-Luc is resolutely still available, but be forewarned — she’s fickle. 🙂
    3. Aaron’s question about beryls/emeralds seems to me more one of nomenclature. Are treated diamonds “really” diamonds of any given color, just because they didn’t come about via Mother Nature? I’m on the fence on that one.
    4. Didn’t mean to knock local businesses and craftsmen because I’m generally a big fan, particularly of fine craftwork in jewelry. But the guy I went to wasn’t a craftsmen, just a small local jeweler’s shop. I expected a bit more care and attention to detail, because that’s generally what I get when I use small local services. Alas, not in this instance, which is what made it noteworthy. And we did end up taking it back to the place where Future Spouse bought the ring; they fixed it, free of charge. (We’re talking a simple rhodium plating, here, nothing major…)
    5. LabLemming, I’m going to nose around a bit more on the carbonado front and see if I can’t come up with a suitable “spin” to make the Kagi paper more palatable to the media — it would tie in nicely with a post-in-progress detailing a similar ongoing problem with coverage of graphene and metamaterials research. You might get an email if I get stuck on a technical point, though. 🙂

  9. One of the Japanese multianvil labs has been doing some great high-pressure diamond composite stuff- they’ve hit 70GPa in a multianvil, which as far as I know is the current record for that type of vessel. For those experiments, they actually use a large volume, lower pressure run in WC to synthsize their diamond parts for the super high pressure stuff. Crazy, but after one of them gave a talk here, our high pressure tech said to me, “That must be, like, our entire annual budget for just one run”.
    As for the Garai paper, just consider the following exerpts:
    Section 3.2 Nitrogen-related bands
    “… The peak at 1102 cm-1 (9.07 m) is relatively wide (FWHM = 103.6 cm-1) and asymmetric with a shoulder, indicative of two peaks. Spectral analyses show peaks at 1100 cm-1 (9.09 m) and 1128 cm-1 (8.86 m) that reproduce the observed spectra. The 1128 cm-1 is attributed to substitutional nitrogen.”
    So: peak stripping reveals the N peak at 1128 cm-1 (within error of the textbook value)
    Section 4 Conclusions
    “The strongest absorption band at 1102 cm-1 (9.04 m) is most likely due to substitutional nitrogen in hydrogenated diamond”
    Astronomers may be different, but in geology is considered bad manners to switch your peak attibutions halfway through a paper.

  10. After reading this, I beginning to think that Superman wouldn’t be able to squeeze a lump of coal into a diamond, unless he also used his heat vision at a couple of thousand degrees Kelvin. Man, is Lois going to be pissed!

  11. With diamond coloring, the actual defects responcible for the color that are induced synthetically are different to the ones found in nature, but they can be combined to appear similar to the eye. This is just like pictures on a computer screen- if you were to take the spectra of a computer image of an orange, it would look nothing like the spectra of sunlight reflecting off of an actual orange. But to the human eye they look fairly similar.
    A few decades ago, when the Argyle diamond mine went into production, they realized that they had a huge supply of yellowish-brownish diamonds- the color was caused by defect induced by plastic deformation, as the diamonds there come from hotter, deeper mantle than the diamonds in most mines.
    For years, the diamond people sent these stones to labs, asking them to find ways of decolorizing the stones in undetectable ways. These efforts were expensive, and fruitless. Eventually, they gave up on the research program, and hired a marketting consultatnt. The consultant branded the mud colored diamonds as “champagne” diamonds, a rare, unique, and distinctively Australian variety. See their fancy words for “mud-colored” here: http://champagnediamondcenter.com/index.html

  12. (As yet, there is no “acceptable” term for the practice of converting the carbonized remains of loved ones into “memorial diamonds,” a la the LifeGem Company.)
    Well they did say she was a ‘real’ diamond in life
    Sorry to hear about the first jeweller. Dentists like to charge even more than jewellers, but their work is usually just as shoddy (close-up) a long shot from the smooth or polished finished one would expect for the prices they charge. One just cannot get the labour, or find the craftmanship you’d expect from a real ‘artisan’ or jeweler nowdays

  13. Very interesting! It actually made sense to me (because you’re awesome, Jennifer)! As an art historian and anthropologist, when I think of diamonds and precious metals, I definitely don’t think of their chemical composition. First thing that comes to mind is that the diamond industry is a horrible, horrible entity that costs human lives. And this definitely is not to make anyone feel bad about wearing or owning diamonds because they really are quite pretty and especially if we receive one from someone we love, we appreciate and cherish the gift–it’s one of the most prominent cultural symbols of love in our society. However, our cultural practice of diamond engagement rings is built on exploitation and slavery, it fuels civil wars, funds illegal weapons trades. And Cecil Rhodes, who founded deBeers Diamond, was a real bastard–he was pretty much one of the biggest supporters of instituting apartheid in South Africa. So, I hate deBeers, and I Damian not allowed to get me an engagement ring when we got married. That was my tiny little protest against The Man. 😉

  14. Partly due to the diamond industry’s marketing pressure and partly due to cusrtoms from my original locale, the engagement rings me and my wife wear are plain gold bands (yep, identical design, one for her, one for me), at the lowest grade I’d consider for skin-contact gold jewellery, 18K (co-incidentally, the lowest grade of gold that can be vended as “gold” in Sweden).
    I must agree that diamonds are pretty, though.

  15. I’ve always just assumed it was better to buy manufactured gemstones rather than genuine ones, since I thought that it was less likely to fund a horrible industry, and I could never tell the difference. Could someone tell me if this is true, or is the money still supporting the same companies? I’ve never checked to see if my assumptions are correct.

  16. Booshi:
    Horrible is a relative term, when applied to industry, economics, and politics. Debswana was one of the first companies in Africa to offer retroviral treatment as part of the employee health plan. Buying synthetic diamonds won’t help narrow the income gap between rich and poor countries. But if only 1% of the diamond value actually gets to those countries, neither will buying natural stones.

  17. So, you were adamant that your adamant be handled with integrity! Yes, it seems more difficult these days to find good workmanship with shoes, jewelry, etc.; one has to find a person who considers it almost an art form.
    I like the literary quotes in Wikipedia in reference to “adamant”: http://en.wikipedia.org/wiki/Adamant
    Though I think the Wiktionary entry does the word a little more justice: http://en.wiktionary.org/wiki/adamant
    I’ll have you know, too, that after that discussion about diamond anvils last Fall, especially SteveT’s experienced input, I looked up Google images of them:
    http://images.google.com/images?svnum=10&hl=en&gbv=2&q=diamond+anvil&btnG=Search+Images
    I can see how they would be nerve-wrackingly fun.
    Also, I hope we get to see a pretty picture of you and the ring on your finger…with Future Spouse, of course. 🙂

  18. Ouch? Why ouch? Surely you don’t mistake me for some shallow creature who thinks the size of the diamond(s) is the true and final arbiter of how much her betrothed loves her! The ring is lovely, and more importantly, it’s the one my fiance picked out on a whim when he decided to propose. No other ring would carry the same meaning and hence would be of lesser value, regardless of the size of the stone(s). Okay, the wedding ring will be that meaningful… but that’s just going to be a simple band…

  19. “Surely you don’t mistake me for some shallow creature who thinks the size of the diamond(s) is the true and final arbiter of how much her betrothed loves her! ”
    Of course not. But I don’t think any guy particularly wants to hear the diamonds described as ‘small’, whether they are or not, especially when the word is kinda superfluous in context.
    Clearly, they’re not ‘small’, they’re ‘just right’.

  20. I grew up with a mom who had inherited a huge diamond from her parents. She wore it everday because my parent could not afford to insure it. Also it was the sentimental value and not replaceable anyways.
    I worked in a jewelry store in High school and to this day I love big rocks. Now they facinate me more even from a geological standpoint. My husband and I could and should not afford a big rock so I have a personally designed wedding ring with my grandpa’s gold and my grandmom’s baguettes. It is priceless to me.
    The real reason I am commenting is to thank you for thee link to Life Gems. Hey if I can’t have a big rock, I can be made into one. How wonderful and cool. Solves my burial problems!!!

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