How to Identify a Mineral

Want to know the type of rock or mineral you just found? Follow these steps and then compare your results to a chart of rock and mineral types.

Difficulty: Easy

Instructions

Things You'll Need:

• Rock and Mineral Guide

1. Mineral Identification Step #1: Color - Determine the color of the rock or mineral and then determine whether it is opaque or translucent.

2. Mineral Identification Step #2: Luster - Determine whether the mineral is shiny or dull and whether or not it has a metallic or non-metallic luster.

3. Mineral Identification Step #3: Texture - Determine whether the rock or mineral is bumpy, smooth, sugary, jagged, or other texture.

4. Mineral Identification Step #4: Hardness - Moh's Hardness Scale (H) ranks the hardness of minerals from 1 to 10. Talc is the softest and diamond is the hardest. To test the hardness of a mineral, try scratching the mineral with a common object such as a fingernail (which has a hardness of 2.5), a penny (with a hardness of 3), a knife or piece of glass (H=5.5), and a steel knife (H=6.5).

5. Mineral Identification Step #5: Crystalline Structure - Determine whether the mineral has a crystal shape, and if so how many sides the crystal has. Also determine if the crystal structure is grooved or smooth on the outside and if it is stubby or long and slender.

6. Mineral Identification Step #6: Specific Gravity - Determine if the mineral is light weight or unusually heavy for its size.

7. Mineral Identification Step #7: Streak - Determine what the color of the mineral when it is ground into a powder. To test streak of a mineral in the field, rub the mineral on a piece of unglazed porcelain.