Luster

Luster is the way a mineral’s surface reflects light, giving it a shiny or dull appearance. It describes how lustrous a mineral looks when light hits it, similar to how metals like gold or silver shine, or how a rock might look matte or glassy. Luster can be described as metallic, shiny, glassy (vitreous), dull, silky, or earthy, among others. It helps in identifying minerals, as different minerals have characteristic lusters. Essentially, luster is a visual property that reveals how a mineral interacts with light on its surface.