This story goes a while back. Until about a year ago, I worked at a jewelry store. Part of my job was to clean the parts of the store that had hardly been glanced at in about fifty years, and one of the perks was that I could ask to take almost anything I found home. In one pile on a box that was 90% polishing wheel cloth scraps and polishing dust, I found some awesome stuff. One, my current main watch. Two, an 8oz. bag of 18k casting gold, stamped and with a receipt from 1955. My employer didn't let me keep that one.
Third, and the point of this story, a sapphire watch crystal.
My boss let me take the crystal, so that day I came home hoping to test out just how tough sapphire is. I cut papers with the edge of the crystal, but it wasn't really sharp. No surprise there. I scratched my pocketknife and failed to scratch my mother's diamond. Normal tests. About a week after I got the crystal, I rediscovered it on my desk and was playing with it when I dropped it on the cement in the garage. I expected it to chip, but it was unharmed when I checked it over. Naturally, that made me wonder just how impact resistant the crystal was. I figured that other than for testing hardness, the stone would be fairly useless to me.
Anyway, I grabbed a screwdriver, hammer, and some safety goggles. I placed the crystal flat on the concrete and swung the hammer as hard as I could onto the crystal. The hammer head was dented, but that's all that happened. I tried the same experiment with the screwdriver focusing the force with similar results. I positioned the crystal on our steel vice, straddling the gap, with the screwdriver focusing the blow again. I figured that I might as well break the persistent bugger and get some entertainment for my trouble, but, as you may have guessed, the crystal survived, leaving the vice with some marks and the screwdriver a bit dull-headed.
I still have the crystal, and rediscovered it most recently last night. My brother and I got to talking (he was there when I duplicated the experiments to show that I wasn't crazy) about the use of a stone that hard and shatter-resistant. Being the crazy fantasy reader I am, my first thought was a sapphire sword. Making an entire blade of saphire would be impractical, but having a nicely rigid metal I-beam core would be decently light and lend some semblance of financial practicality to the project. (Says a broke college student.
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Sapphire can be made to be very sharp, would be resistant to dulling, etc. Basically all of the characteristics of a ceramic blade, but a little harder and infinitely cooler. The only Google result of any usefulness I got for any variation of corundum/sapphire/aluminium (tri)oxide blade/knife/sword is here:
bob-basset's livejournal. The link's in Russian. Here's Google's translated version:
woo, language!The discussion last night included crysknifes, glass daggers used by Mistborn, and the RPG series Elder Scrolls' weaponry (Glass weapons are made of green volcanic glass, Ebony and Daedric are made of obsidian.
The Daedric dagger from Morrowind looked sweet.). These were just the examples that sprung to mind, but I'm sure there are many other stories that use transparent stone weapons.
To sum up, sapphire is surprisingly strong, and I'm impossibly long-winded and nerdy. I could ask a synthetic sapphire manufacturer about a 6-8" knife blade made to my specs for mounting on a metal rail. Watch crystals are pretty cheap, but a custom job like that wouldn't be. Ah, if only I had money to burn for ridiculous projects like this. I guess it's better (more practical and inexpensive) than my original idea for a micro-serrated diamond blade edge. A super high-tech sword would also be awesome for its capacity to baffle future archeologists.