Never underestimate the power of a slick marketing campaign to hornswaggle and bamboozle people into thinking a worthless product is attractive and valuable. Black diamonds, or carbonados, have historically been viewed as ugly and cheap and not of gem quality, for a very simple reason: they don’t have much clarity so they lose the optical properties and luster we associate with diamond gems.
However, thanks to aggressive salesmanship and advertising, black diamonds are now selling at prices equal to those of “white” diamonds, despite the fact, in all honesty, close up they’re pretty ugly: they typically have the consistency and color of dark sunglasses lenses, a smoky, oily near-transparent gray-black.
I could be wrong, though: here’s Carmen Electra sporting a tasteful and not gaudy at all black diamond engagement ring, and as we all know, Carmen’s both a supergenius and armed with so much taste she’s like the reincarnation of Jacqueline Onassis.
First things first, my lovelies: there’s no such thing as a “black” diamond.
Diamonds are typically single crystals of carbon atoms that are arranged, at the atomic level, into a tetrahedronal (four-sided) crystalline lattice – an arrangement that is called an allotrope, and graphite is another allotrope of carbon atoms. In crystallography, it’s important to remember that something maintains the exact same shape, proportions and series of angles no matter its actual volume or size. That is, a diamond crystal, if not broken, will have these exact same proportions and geometry if it’s an eighth of a centimeter or as big as a fist.
This is called the law of constancy of interfacial angles, or Steno’s law, or, if you prefer, the first law of crystallography, and was discovered in the 17th Century by the great Danish scientist Nicolaus Steno, who helped create the field of modern geology by his discovery of the properties of natural crystals, not to mention other stellar achievements like the idea fossils are the remains of long-dead organisms.
Diamonds are naturally clear, but often when they form, there are occasionally impurities on the level of one part per million – for instance, superheated titanium gas, when caught inside a diamond, forms what’s called an inclusion and often turns the diamond a vivid and unusual color. Boron gases are the source of blue diamonds like the Hope Diamond, for instance.
Colored diamonds are all the rage these days, and have increased in price five-fold: a colored diamond that cost $50,000 in 1970 would be worth several million today. As a result of this, various processes have been created to turn diamonds unusual colors as a result of heat and irradiation. This ends in hilarity and tragedy when a supposedly colored diamond is superheated as a part of repairs only to have it lose its color! The lure of colored diamonds is a relatively recent phenomenon, though! For the majority of history non-colored diamonds were viewed as deficient and cheap.
Black diamonds are not like that, though. Black isn’t a color diamonds come in. Black diamonds are created not by unusual impurities...but by the fact they’re not single crystals, but a polycrystalline aggregate, or more simply, a combination of many individual crystals. Many metals are polycrystalline aggregate, including steel. As a result of this combination, they look an oily black because all the crystals in front of each other prevent the light from going through.
While carbonados may be ugly, the theory about their formation is pretty interesting stuff. They may form in supernovas that compress and expel carbon into polycrystalline aggregates and arrive on earth as meteorites.
In fact, because of their structure and how they form, the largest diamond ever discovered was a black carbonado at 3,147 carats. For comparison, the Hope diamond is 45 carats.
In other words, black diamonds are just repackaged carbonados of dubious non-gem quality that marketing makes you think are cool, sold at high prices because of the demand among the tacky, newly rich demographic, which includes Carmen Electra and most reality show contestants.
The thing that bothers me about marketing is how it can sometimes create an Ouroboros of non-logic and non-causality that could make a time-travelers’ head spin. Black diamonds are viewed as valuable because of aggressive salesmanship, yet their high price is due to demand caused by that aggressive salesmanship. It’s like a paradox used by Captain Kirk to destroy an evil supercomputer.
I don’t get the point of colored diamonds and I particularly don’t care for black diamonds. After all, isn’t the greatest and most beautiful thing about a diamond its clarity and luster and shimmer?
This often surprises people, but not all diamonds are of gem quality – in fact, fewer than half are not used for jewelry at all: most have flaws or problems with clarity and imperfection. In fact, diamonds are a downright miraculous material because of their resistance to heat and hardness used for things like industrial diamond drills and even computers, as any reader of Michael Crichton’s Congo would know.
Here’s another diamond misconception: diamonds form from the compression of coal under intense pressures. Superstrong superheroes like the Thing and the Incredible Hulk regularly squeeze coal hard enough diamonds form. Actually, coal is a type of sedimentary rock left by dead plant matter that was super-compressed, whereas diamonds typically form deep, deep within the earth, in the mantle at depths of several hundred miles in the interior.
The formation of coal is actually extremely unique and interesting. Most people believe that coal is remains of dead dinosaurs. Actually, coal is just compressed peat material from 360 million years, the aptly and descriptively named Carboniferous era, where swamp algae was compressed through a process of lithification, the process by which sedimentary material turns into rock. People know about the supercontinent of Pangea, but Pangea was only the last of several epic supercontinents in the incredible history of the earth. In the carboniferous, most land on earth was at the equator in a supercontinent called Gondwanaland, where it was constantly wet and swampy. Dense, stagnant swamps of non-moving water are typically stripped of oxygen by living things and bacteria, creating anoxic, sulfuric wastes that kill off the bacteteria that result in decomposition, so peat built up in layer after layer for hundreds of feet before it began to lithify.
By the way, no matter how big a nerd you think you are, I know for a fact I'm a bigger one: while cleaning up I found an old "Reunite Gondwanaland" t-shirt.
Also, coal is not entirely carbon at all, which is why it can’t turn into diamond. The composition of bituminous coal (a soft version that leaves an ash residue behind), for instance, is 75% carbon but also includes sulfur, hydrogen and nitrogen, and can also include benzene-like compounds. There are so many different classes of coal that labeling them into categories was a bone of contention among anal retentive petroleum scientists. In fact, burning coals can result in sulfur dioxide, which is the source of “acid rain.”
While I’m at it, let me clear up a common misconception right here: diamonds are not totally indestructible, and they can be broken by enough force and pressure. It is true that only a diamond can cut or scratch another diamond, but given enough pressure diamond can shatter like any other stone. In fact, diamonds, like any carbon allotrope, can even burn at enough temperature. Lavousier, the chemist best known for the discovery of oxygen, discovered that diamonds were principally carbon by measuring what was released from a burning diamond.
In fact, scientists have, under conditions of immense pressure (over ten million pounds per square inch), caused diamond to liquefy. Indeed, there is some speculation that part of the composition of Uranus and Neptune are oceans of liquid diamond. I practically had an orgasm when I heard about that!
You know who would make a good science teacher? Yoda, because he put it best when he said that in science, knowledge is unlearning a lot of what you have learned.
What’s the point of all this? Well, it just goes to show how an understanding of Geology can help people navigate through important purchases and important decisions, because many things we think we know are actually untrue or wrong. One big problem is how many garnets, a pinkish and cheaper stone, are often mislabeled as rubies. This was especially common in the past, where there was no x-ray crystallography and other methods to definitively identify gemstones. Just like diamond is a crystalline form of carbon, rubies are a typical form of the silicate mineral corundum, which incidentally, also is the source of amethysts.
Finally…what’s my favorite gemstone, you may ask?
Well, ask any rockhound that and you’ll get a hundred that come to mind, but that depends if you mean precious gemstone or not.
My favorite non-precious stones are a variety of crystalline quartz found in upstate New York called Herkimer County Diamonds. The reason I like these the best is that they’re photogenic, huge and clear and terminate at either end in points, and also because I had the good fortune of finding one on my first rockhound trip to upstate NYC. It’s not a protected resource so you can just pluck ‘em off the ground if you like, and they’re super-photogenic; when I show people my rock collection eyes immediately migrate to them. Also, they are found by just cracking open rocks, just like in the movies!
As for my favorite precious gemstone, I would have to say a beautiful, rare and unusual variety of burnt-orange garnet called spessartine, a manganese aluminum silicate that was mostly unknown until deposits were found between Nairobi and Angola. Even today it’s as hard to find as it is gorgeous.
