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:
“We are compelled by the theory of God’s already achieved perfection to make Him a devil as well as a god, because of the existence of evil. The god of love, if omnipotent and omniscient, must be the god of cancer and epilepsy as well.... Whoever admits that anything living is evil must either believe that God is malignantly capable of creating evil, or else believe that God has made many mistakes in His attempts to make a perfect being.”
—George Bernard Shaw (1856–1950)
“It is crystal clear to me that if Arabs put down a draft resolution blaming Israel for the recent earthquake in Iran it would probably have a majority, the U.S. would veto it and Britain and France would abstain.”
—Amos Oz (b. 1939)