Luster what is

It consists of 6 whorls, which glisten with that peculiar spun-glass or flossy luster noticeable in so many abyssal species.

It is a translucent white triclinic mineral with a waxy luster. See all examples of luster. These examples are from corpora and from sources on the web. Any opinions in the examples do not represent the opinion of the Cambridge Dictionary editors or of Cambridge University Press or its licensors. What is the pronunciation of luster? Browse lusophone. Test your vocabulary with our fun image quizzes.

Image credits. Word of the Day have a heart of gold. Blog Outsets and onsets! Read More. November 08, To top. English American Examples. Vitreous - This luster accounts for roughly 70 percent of all minerals. Minerals with a vitreous luster have reflective properties similar to glass.

Most of the silicates , carbonates , phosphates , sulfates , halides , and hydroxides have a vitreous luster. Adamantine - Transparent to translucent minerals with a high refractive index yield an adamantine luster, meaning they display extraordinary brilliance and shine.

Resinous - This is the luster of many yellow, dark orange, or brown minerals with moderately high refractive indices - honey like, but not necessarily the same color. Silky - A silky luster is the result of a mineral having a fine fibrous structure. Minerals with a silky luster have optical properties similar to silk cloth.

Pearly - Describes a luster similar to the inside of a mollusk shell or shirt button. Many mica s have a pearly luster, and some minerals with a pearly luster have an iridescent hue. Not the riding of course—that part never loses its luster —but everything that comes with it. Many experts say that the Siberian tundra has lost its luster since its Ice Age heyday.

Yet when our speedster pauses for just a moment, the luster of The Flash fades. He has already developed a hair product that enhances the luster of red hair and has plans for more products. Palin arrived at CPAC with her once-blinding luster seriously dimmed. Needless to say, the gallows humor that is a hallmark of my former profession has lost much of its luster.

Luster says he believed his antiques and other possessions would be sold, with the proceeds going to his two young children. That allows the light that strikes the specimen to reflect to the eye of the observer. Proper examination includes moving the specimen or the light source, or the head of the observer through a range of angles to observe the full character of the luster. The photographs and descriptions on this page illustrate some of the most common lusters observed in minerals.

Silver Metallic Luster in Galena: This photograph shows the silver metallic luster of a nice cubic crystal of galena. The galena crystal is about two inches on a side, and the adjacent white crystals are calcite. Specimens with a metallic luster exhibit the reflectivity and brightness of a metal and are always opaque. The smoother the surface, the brighter their luster, and the higher their reflectivity.

When a beam of incident light is reflected from a perfectly smooth reflective surface, the angle of reflection is equal to the angle of incidence. Smooth surfaces have higher lusters because all of the light that strikes them has an opportunity to be reflected. However, when light strikes a rough surface, much of the light is hitting irregularities in the surface. This light is scattered in many directions.

These specimens with an irregular surface will have a lower luster than specimens with a smooth surface. Most metallic minerals have a color similar to native metals such as gold , silver , or copper. Just because a specimen is highly reflective does not give it a metallic luster.

It must also be opaque and exhibit the color of a metal. Opacity is an important part of a metallic luster. Light enters specimens that are transparent or translucent. When a specimen is opaque, then all of the incident light has an opportunity to be reflected.

Many sulfide and sulfosalt minerals have a metallic luster, such as pyrite , galena , chalcopyrite , and pyrrhotite. Some oxide minerals such as hematite , rutile , magnetite , and cassiterite may exhibit a metallic luster. Submetallic Luster in Magnetite: A specimen of magnetite variety: lodestone exhibiting a submetallic luster. The specimen has attracted numerous tiny particles of iron. This specimen is approximately 10 centimeters across.

Some specimens exhibit a luster that falls short of being called "metallic" or makes the observer doubtful about using that adjective. The word submetallic might be used for these specimens. These specimens are usually opaque, and they are often black in color. Others have a small grain size, or an irregular or pitted surface that interferes with the reflection of incident light. Observers should be careful, because tarnish will sometimes mislead them into deciding that a specimen is submetallic rather than metallic or nonmetallic.

This is when observations of luster on a freshly broken surface become important. Hematite , magnetite , graphite , and chromite are examples of minerals that can exhibit a submetallic luster. Most mineral specimens do not exhibit a metallic or submetallic luster. These specimens are said to have a "nonmetallic" luster. There are many varieties of nonmetallic lusters, and the most common are described below. Note: The name "nonmetallic" applies to the luster of these minerals and has nothing to do with their elemental composition.

Nonmetallic Vitreous or Glassy Luster in Apatite: These small greenish yellow crystals of apatite exhibit a vitreous luster. Vitreous means "the appearance of glass". Some people would call this a "glassy" luster, and that would be perfectly correct. The apatite crystals are from Cerro del Mercado, Durango, Mexico, and they are mostly about 8 millimeters in length. Image copyright by Geology.