* Physical Properties: These are characteristics of a substance that can be observed or measured without changing the substance's chemical composition.

* Chemical Properties: These describe how a substance reacts with other substances or how it changes its composition.

Metallic luster refers to the shiny appearance of metals. This property is due to the way light interacts with the surface of the metal, not a change in the metal's chemical makeup.

Here are some examples:

* Gold: Gold is shiny whether it's in a nugget or a thin sheet. Its chemical composition remains the same.

* Silver: Silver tarnishes over time, but this is a chemical change (oxidation) that alters its surface and causes the luster to diminish.

In summary: Metallic luster is a physical property that describes how light interacts with a metal's surface. It doesn't involve a change in the metal's chemical composition.