Understanding Mineral Luster Characteristics

The video tutorial explains the concept of luster in minerals, focusing on how light reflects off mineral surfaces. It covers two main types of luster: metallic and non-metallic. Metallic luster is compared to the reflection off aluminum foil, while non-metallic luster is divided into categories like vitreous, resinous, silky, pearly, greasy, and earthy. Each type is described with examples, highlighting how luster is independent of mineral color. The tutorial emphasizes the importance of good lighting for observing luster and provides a detailed comparison of different luster types.

What is the primary factor to consider when observing the luster of a mineral?

• The type of light used

• The color of the mineral

• The weight of the mineral

• The size of the mineral

How does metallic luster appear on a mineral surface?

• Like light reflecting off silk

• Like light reflecting off a diamond

• Like light reflecting off aluminum foil

• Like light reflecting off glass

Which statement is true about metallic luster?

• It depends on the mineral's color

• It is independent of the mineral's color

• It is only found in gold-colored minerals

• It is the least reflective type of luster

What is a characteristic of vitreous luster?

• It reflects light like a diamond

• It reflects light like silk

• It reflects light like broken glass

• It reflects light like a pearl

Which luster is more reflective than vitreous but not commonly shown in courses?

• Resinous

• Silky

• Adamantine

• Earthy

What type of luster does amber typically exhibit?

• Vitreous

• Silky

• Earthy

• Resinous

Which luster is described as having a diffuse sheen similar to silk?

• Pearly

• Greasy

• Silky

• Earthy

What is a defining feature of greasy luster?

• It has an oily sheen

• It is highly reflective like glass

• It is completely non-reflective

• It has a pearly iridescence

Which luster is characterized by a lack of reflectivity, often absorbing light?

• Silky

• Earthy

• Resinous

• Vitreous

In the context of non-metallic lusters, which is the least reflective?

• Vitreous

• Greasy

• Resinous

• Earthy