Preparation of the Crucible:

1. Heat the crucible and lid with a Bunsen burner over a gentle flame for 5 minutes.
2. After the bottom of the crucible has become red-hot, increase the intensity of the flame.
3. Continue heating the crucible for 10 to 12 minutes.
4. Allow the crucible to cool. Then measure and record the mass of the "fired" crucible.