Luster is a descriptive term used to describe the appearance of a mineral's surface in reflected light. There are many different types of luster, including:

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

* Non-metallic:

* Vitreous: Glassy (e.g., quartz)

* Resinous: Like resin (e.g., amber)

* Pearly: Like a pearl (e.g., feldspar)

* Silky: Like silk (e.g., asbestos)

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

* Earthy: Like soil (e.g., hematite)

Luster can be a helpful tool for identifying minerals.