Which term denotes the highest degree of luster in a transparent material?

Which term denotes the highest degree of luster in a transparent material?

• A. Abrasion
• B. Alluvial deposit
• C. Adamantine luster
• D. Bast

Answer: (C)

Adamantine luster describes the brightest, diamond-like shine seen in transparent minerals. It indicates a very high refractive index and strong internal reflections, so light entering the crystal is intensely reflected and dispersed, giving a brilliant, almost glittering glow. This is the top level on the mineral luster scale and is characteristic of minerals with exceptional transparency and brilliance, like diamond. The other terms don’t describe how light interacts with a surface—abrasion is a wear process, alluvial deposit is a sediment type, and bast is plant fiber—so they aren’t relevant to luster.

Adamantine luster describes the brightest, diamond-like shine seen in transparent minerals. It indicates a very high refractive index and strong internal reflections, so light entering the crystal is intensely reflected and dispersed, giving a brilliant, almost glittering glow. This is the top level on the mineral luster scale and is characteristic of minerals with exceptional transparency and brilliance, like diamond. The other terms don’t describe how light interacts with a surface—abrasion is a wear process, alluvial deposit is a sediment type, and bast is plant fiber—so they aren’t relevant to luster.