Clay minerals are too small to clearly identify individual particles. However, they often combine into domains or units that appear to act like a larger entity. Clays often are oriented around pedological features such as voids, mineral grains or structural units. But it may be important to determine whether the clays are oriented parallel or normal to the feature. Useful for determining optical orientation and optic sign of a mineral grain.
Interference figure is a useful diagnostic property for mineral identification.
Last Updated on November 14, 1997.