✍️Activity 3A: Assessing Hardness Values of Minerals

Materials Needed

• Mineral kit, provided by your instructor. This will contain unnumbered samples; use the Mineral Index to order your samples by number. 
• Hardness kit:
  • Your fingernail
  • A copper penny, plate or wire
  • Glass plate or knife blade
  • Steel nail
• Streak plate (unglazed porcelain)
• Hand lens or magnifying glass (at minimum 10x). How do I use a hand lens? Hold it very close to your eye and bring the sample near the lens until it is in focus.

Recall, hardness is the scratching resistance of a mineral. You will need to determine if the mineral is harder or softer than the common material (Table 3.1). Use greater than (>) or less than (<) symbols to indicate the approximate hardness. For example, if your fingernail scratches your sample, look and feel for a gouge or groove in the sample, this sample would represent a hardness value of less than 2.5 (H<2.5).

You will use minerals 9, 5, and 6 for this Activity. Refer to Table 3.1 for guidance.