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 sit in the top of the wood, my eyes closed.
Inaction, no falsifying dream
Between my hooked head and hooked feet:
Or in sleep rehearse perfect kills and eat.”
—Ted Hughes (b. 1930)
“In a few days I’ll have lived one score and three days in this vale of tears. On I plod—always bored, often drunk, doing no penance for my faults—rather do I become more tolerant of myself from day to day, hardening my crystal heart with blasphemous humor and shunning only toothpicks, pathos, and poverty as being the three unforgivable things in life.”
—F. Scott Fitzgerald (1896–1940)