Kristallstorlekar

Kristallstorlekar refers to the dimensions of individual crystals or crystal grains that make up a solid material. In geology it is commonly used to describe the grain size of rocks, such as the size of quartz grains in sandstone or the mica flake size in schist. In materials science and solid‐state physics the term covers the size of crystalline domains in metals, ceramics, and semiconductors, as well as the dimensions of nanoparticles in colloidal solutions.

The size of a crystal influences many of its physical properties. In structural materials, the grain size has a systematic effect on strength, hardness, and toughness; the Hall‑Petch relationship describes how decreasing grain size typically increases yield strength, while very fine grains may lead to embrittlement. In optical applications, crystal size determines scattering and diffraction behavior; for example, large‑grain sapphire crystals are used for laser windows because they reduce optical loss. In geotechnical engineering, the grain size distribution of aggregates affects the compaction, permeability, and load‑bearing capacity of foundations.

Crystal size can be measured by several techniques. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) provide direct imaging of individual grains at micro‑ to nanoscale resolution. X‑ray diffraction (XRD) can estimate average crystallite size through peak broadening using the Scherrer equation. For bulk rocks, the Anderson or Folk‑Kraemer grain‑size tables are standard, based on visual assessment under a hand lens or microscope.

Accurate determination of kristallstorlekar is therefore essential for predicting material performance, interpreting geological histories, and designing advanced technologies.