Quasicrystal

October 29, 2007

I have a love of symmetry and order that does not reflect in any way my day to day life.

Quasicrystals are like ordinary crystals in that they diffract light, but they lack any long range order. In other words, real crystals have translational symmetry; they are periodic, so you can shift a copy up, down, left, or right and it will fit back on the original crystal. With quasicrystals, if you try to do this, it will never match. It’s like a key with only one lock. Believe me, i’ve tried.

Here is a quasicrystal formed by a complex metal alloy:

quasicrystal.jpg

By the way, The Darjeeling Limited is worth watching if you like pointless movies with good visualsĀ  but where nothing much happens.


Medieval Islamic Quasicrystal

October 21, 2007

penrose_3.jpg

Lu, P; Steinhardt, P. J. “Decagonal and Quasi-crystalline Tilings in Medieval Islamic Architecture” Science, 315, 1106 (2007)