Twinned crystals

Twinned crystals may take a variety of forms. The most common types of twinning are:

* Contact Twins
* Penetration Twins
* Repeated Twins

Chesterman, p. 39

## Sources[edit]

* Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf: New York (1987)