Crystalline materials (mainly metals and alloys, but also stoichiometric salts and other materials) are made up of solid regions of ordered matter (atoms placed in one of a number of ordered formations called Bravais lattices). These regions are known as crystals. A perfect crystal is one that contains no point, linear, or planar imperfections. There are a wide variety of crystallographic defects.
The hypothetical concept of a perfect crystal is important in the basic formulation of the laws of thermodynamics.
In crystallography, the phrase 'perfect crystal' can be used to mean "no line or planar defects", as it is difficult to measure small quantities of point defects in an otherwise defect-free crystal.
Imperfections are created due to gravity. In space and in zero gravity environments perfect crystals can be created as on the International Space Station.
Famous quotes containing the words perfect and/or crystal:
“I say to you: Make perfect your will.
I say: take no thought of the harvest,
But only of proper sowing.”
—T.S. (Thomas Stearns)
“If Los Angeles has been called “the capital of crackpots” and “the metropolis of isms,” the native Angeleno can not fairly attribute all of the city’s idiosyncrasies to the newcomer—at least not so long as he consults the crystal ball for guidance in his business dealings and his wife goes shopping downtown in beach pajamas.”
—For the State of California, U.S. public relief program (1935-1943)