A
single crystal or
monocrystalline solid is a material in which the
crystal lattice of the entire sample is continuous and unbroken to the edges of the sample, with no
grain boundaries. The absence of the defects associated with grain boundaries can give monocrystals unique properties, particularly mechanical, optical and electrical, which can also be
anisotropic, depending on the type of
crystallographic structure. These properties, in addition to making them precious in some gems, are industrially used in technological applications, especially in optics and electronics.