#solid state physics
- Allochromatism — The property of certain minerals or crystalline substances to exhibit diverse colors due to the presence of fine chemical impurities, foreign inclusions, or defects in the crystal lattice, rather than their basic chemical composition. In their pure state, these minerals are usually colorless or white, the final color being accidentally determined by external factors during crystallization.
- Amorphism — The state, property, or character of being amorphous; the total absence of an ordered crystalline structure or a regular geometric shape within a solid body. In mineralogy and crystallography, this phenomenon reflects long-range structural molecular disorder, causing isotropic properties that remain constant in all spatial directions.