Luster is a descriptive term used in geology to describe how light reflects off the surface of a mineral. There are many different types of luster, including:

* Metallic: Looks like polished metal (e.g., pyrite)

* Vitreous: Looks like glass (e.g., quartz)

* Resinous: Looks like resin (e.g., amber)

* Pearlescent: Looks like a pearl (e.g., muscovite mica)

* Silky: Looks like silk (e.g., asbestos)

* Dull: No shine (e.g., clay)

Let me know if you'd like to know more about any of these luster types!