EARTHSC 1108 Lecture Notes - Lecture 5: Olivine, Polarizer, Refraction
Document Summary
We see color when a material (gem) selectively absorbs specific wavelengths of visible light: luster. External reflection of light in gems surface depends on refractive index of each stone. The higher the ri the highest the luster, not measurable so described with names. How well light passes through a stone, what limits transparency? (i. e. what makes gems opaque?) Inclusions, gas/liquid bubbles, fractures or fissures, grainy or fibrous growths within a crystal. Light is an em vibration at a specific wavelength. The most familiar part (to humans) of the electromagnetic spectrum is the visible region, which spans the colors of the rainbow. We are able to see things bc our eyes are sensitive to this region of the spectrum. Reflection- when light enters an object: part of that light is reflected: *light behaves this way in every facet of a gem. Refraction- when light enters an object: part of that light is absorbed and refracted: