Indiana Kat and the Kingdom of the Crystal Skull
I was googling around for pictures of various crystals because I'm putting together a presentation about mineralogy in everyday life for high school students (or the German equivalent) as part of a week long orientation course at my university that includes pretty much every major available. Anyway, I stumbled across this, a site about those famous and *MYSTERIOUS* quartz crystal skulls. I should have stayed away from it, because they always mangle the science and I always get annoyed, but my case of train wreck syndrome must have gotten worse or something.
I particularly like this part about the so called Mitchell-Hedges skull:
Researchers found that the skull had been carved against the natural axis of the crystal. Modern crystal sculptors always take into account the axis, or orientation of the crystal's molecular symmetry, because if they carve "against the grain," the piece is bound to shatter -- even with the use of lasers and other high-tech cutting methods.
Yeah, except not. *goes into lecture mode* Quartz does not shatter if you try to sculpt it, even if you go against its 'natural axis'. Quartz crystals along with every other crystal (except very low symmetry ones) contain several symmetry axes that are the result of its structural symmetry. It is possible for crystals of some minerals to cleave and shatter, if you apply pressure along the wrong axis. I assume that's what they mean by 'carving against the natural axis'. However, Quartz is not one of those minerals. Carving it along different directions with the appropriate tools, say diamond, is no problem, if you take into account that its hardness will vary a bit for different directions.
I particularly like this part about the so called Mitchell-Hedges skull:
Researchers found that the skull had been carved against the natural axis of the crystal. Modern crystal sculptors always take into account the axis, or orientation of the crystal's molecular symmetry, because if they carve "against the grain," the piece is bound to shatter -- even with the use of lasers and other high-tech cutting methods.
Yeah, except not. *goes into lecture mode* Quartz does not shatter if you try to sculpt it, even if you go against its 'natural axis'. Quartz crystals along with every other crystal (except very low symmetry ones) contain several symmetry axes that are the result of its structural symmetry. It is possible for crystals of some minerals to cleave and shatter, if you apply pressure along the wrong axis. I assume that's what they mean by 'carving against the natural axis'. However, Quartz is not one of those minerals. Carving it along different directions with the appropriate tools, say diamond, is no problem, if you take into account that its hardness will vary a bit for different directions.