The Michel Levy scale of retardation colour is a term used in optics to describe the colors produced when light is passed through materials that exhibit birefringence. The word "retardation" describes the delay in the phase of light as it passes through such materials. The IPA phonetic transcription of "Michel Levy scale of retardation colour" would be /mɪˈʃɛl ˈlɛvi skeɪl əv riː.tɑːrˈdeɪʃən ˈkʌlər/, with the stress falling on the second syllable of "retardation" and the first syllable of "color".
The Michel-Lévy scale of retardation colour is a scientific measurement used in the field of optical mineralogy to quantify the birefringence of minerals. Birefringence refers to the property of certain materials, such as crystals, to split light into two different polarized rays when it passes through them. The Michel-Lévy scale provides a standardized and quantitative way to evaluate and communicate the level of birefringence observed in a mineral sample.
Developed by French mineralogists Auguste Michel-Lévy and Gustave Lévy in the late 19th century, the scale is composed of a series of standardized colors that correspond to specific levels of retardation. Retardation refers to the phase difference between the two ray paths produced by birefringent materials.
The scale assigns values from 1 to 10, with 1 representing no retardation (or isotropic behavior) and 10 representing the highest degree of retardation. Each value on the scale is associated with a specific color, allowing mineralogists to easily communicate and compare the level of birefringence observed under a polarizing microscope.
The Michel-Lévy scale of retardation colour is an essential tool in the identification and classification of minerals. By assessing the retardation color of a mineral sample, mineralogists can gather valuable information about its internal structure and composition, aiding in its overall characterization and classification.