It’s odd that this hasn’t been discussed. I searched the forums but no mention of diamonds themselves. Just their uses in cultuire.
Fine and good.
Diamond is 10 on Moh’s scale of hardness, which means that if you scratch something with a lower Moh’s number with little force onto a face of a diamond, the point of the other something will break. And you can carve your initials into a ruby if you like with a diamond.
Mind, I know that hardness itself isn’t really all that useful. I collect swords, and know that with simple steels, rather than modern ones, you have to make a tradeoff between hardness and flexibility. A modern blade made by a mster is very hard and inflexsible and will not break nearly as easily as an old-style blade that’s the same very hard and inflexible. Brittleness of the steel, you see.
What was I talking about? Oh right. Moh’s scale refers to what scratches what at very low veolicites. Diamond scratches tempered glass. A diamond will shatter if dropped on a hard floor, but a piece of tempered glass will not.
Is there anything harder than diamond? Even theoretically? I know that diamond is exceptionally strong because of carbon’s outer shell of electrons - 4 electrons, 4 spaces. An excellent situation for collections of pure carbon to bond with the 4 closest carbon atoms, each bond a strong one.
Can anything else form crystals with the same arrangement? The others in carbon’s column on the Periodic Table should bechave similarly, like silicon and germaniuim.
Anyway, any ideas? Or perhaps predictions on the future production of said superhard stuff?
My books are all up at my office, but IIRC, some synthetic diamonds are >10 on Moh’s scale (but not by much). And I think Silica Carbide may come close, but falls short of 10.
Also, note that it’s not just how carbon bonds, but how it is coordinated with other carbons. Diamonds are tough not just because of the strong covalent bonds of C, but because each carbon atom is in a tightly-packed coordination with four other C atoms (IV-coordnation, or “tetrahedral” coordination). Graphite (H ~ 2.5?), on the other hand also consists of covalently bonded C… but each C atom is in III-fold (“plane”) coordination instead of IV, and forms sheets that bond with each other with weak Hydrogen or Van der Waals bonds.
In short: it’s not just the C’s, it’s how you pack 'em.
Nanotubes and bucky balls I’d assume. I don’t have all that much information on the topic but IIRC if you zoom in on Carbon close enough you’ll see little tubes that are really really strong. Therefore if you make something out of those little tubes it is also very very strong. More so than diamonds. Same concept for buckyballs.
Don’t confuse “hardness” with “strength”. Hardness only refers to a mineral’s ability to scratch (or resist scratching); natural weaknesses in the lattice planes of many minerals (including Diamonds) will cause them to cleave (break along planes) quite easily.
Example: Diamond (H10) is considerably harder than quartz (H7), but is much less durable under stress–a slight tap in the direction of a cleavage plane will cause Diamond to break along that plane, but it takes a great deal more force for quartz to fracture because it lacks those internal weaknesses. Similarly, buckyballs, nanotubes, et al., may be stronger than diamond, but that does not make them necessarily harder.
The Mohs scale is simply an empirical ranking and not very accurate. A more scientific measure is the Knoop scale, which is based on measuring the “micro-indentation” of a mineral. On that scale diamonds measure an average of 7000 with a peak of 8400, five times harder than corumdum.
It has been calculated that a hypothetical arrangement of atoms called beta-carbon nitride might be even harder than diamond. But so far it has not been successfully synthesized.
I read somewhere that boron nitride might be as hard as diamond. The Britannica only says that “it is second only to diamond in hardness” and “approaches” 10 on the Mohs scale.
Sure. Silicon dioxide (the main component in sand) is arranged exactly like diamond. But whether germanium has such properties is not known. Germanium, unlike silicon and carbon, is a semimetal and displays metallic properties. There’s germanium nitride (Ge[sub]3[/sub]N[sub]4[/sub], a giant covalent molecule, but I don’t know it’s exact hardness.
When I was a kid, I learned that Borazon was harder than a diamond, and carborundum might be, too.
Then you find things like this:
http://newton.dep.anl.gov/askasci/chem00/chem00262.htm
nobody actually comes out and says that Borazon is harder than a diamond, or even guarantee that it is as hard as a diamond anymore. I suspect those initial gasps at Borazon’s hardness were advertiser’s hype.
(hijack)
Organic, at least where I do my work, refers to something that usually contains around 3 of the four common organic elements- C H O and N. For example, sodium bicarbonate isn’t organic in the sense that ethylene glycol is.
In any event, diamonds, whatever you call them, are highly resistant to chemical corrosion. So are most of the metals used in jewelry. So the diamonds would certainly survive the experience, and probably so would the rest of the earring.