✍️Activity 3A: Assessing Hardness Values of Minerals

Materials Needed

• Mineral kit, provided by your instructor. This will contain unnumbered samples; use the Mineral Index Download 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 Links to an external site.? 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.