Introduction to Franklin micro-minerals
What is SEM ?
SEM stands for scanning electron microscope, a principal research tool for the study of surfaces at high magnification.
Samples are placed in an evacuated chamber and bombarded by a carefully focused beam of electrons, and the secondary electrons are collected, amplified and used to form an image, typically on a television screen, of the sample's surface.
Details smaller than one-tenth of a micron are routinely visible with most machines. Samples are generally first made conductive through a microscopic coating of carbon or a special metal alloy. No colors and no internal structures are visible using SEM, but superb surface images can be easily prepared.
A large number of Franklin-Sterling Hill minerals occur in secondary micro-crystals, and these are often exquisitely formed. Such samples provide fascinating material for detailed SEM study.
Take a look at some of the SEM images listed at upper left under 'selected species'.
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