Electron microscope observation of dislocations in talc

Dislocations in talc appear to be dissociated into four partial dislocations separated by their stacking fault ribbons. This phenomenon can easily be interpreted in terms of the known structure of talc. The stacking fault energy can be estimated from the equilibrium condition of the four partials. Complicated networks resulting from the interactions of ribbons are observed. A number of striking contrast effects are also described.