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Photographic gallery.  Thousands of particles under the microscope.
Microcrystal Test for Sulfur or Calcium

Calcium Sulfate Dihydrate

This is a calcium sulfate percipitate formed by the addition of dilute sulfuric acid to a solution containing calcium chloride. In this case the test drop was very concentrated. For more typical crystals look under "Chemical Microscopy"

Transmitted Off Crossed Circular Polarized Light

Definition/Function:

Significance in the Environment:

Characteristic Features:

Associated Particles:

References:

Chamot, Emile Monnin and Clyde Walter Mason, HANDBOOK OF CHEMICAL MICROSCOPY, Volume II, pp. 105-107 and 349-350, 1940.