Reality → Matter → High-tech materials
Crystals. The structure of crystals plays an important role in condensed matter and solid state physics. X-ray crystallography contributed to chemistry and materials science, and is the primary tool used to determine the structure of biomolecules. In the 1980s, quasicrystals with ordered structure that lacks the periodicity of crystal lattices were discovered (see also Penrose tiling and the 2011 Nobel Prize for Chemistry).
Conductors. For practical and engineering purposes, the conduction of electricity in metals is sufficiently described by Ohm's law. Quantum mechanics provide a more fundamental explanation based on the free electron model. Quantum mechanical effects also show in ferromagnetism and superconductivity.
Semiconductors. The abundant chemical element silicon has become the predominant semiconductor through its use in solar energy and electronics. Purified (>99.9% Si) polycrystalline silicon dominates in photovoltaics, and extremely pure (99.9999999% Si) monocrystalline silicon is the primary material in chip manufacturing. The quantum mechanical band theory is at the base of the epoch-making transistor.