SCSP

What is diatomaceous earth?

Diatomaceous earth is made up of diatoms, which are unicellular algae whose cell walls are constructed of silica. The cell walls can form many different shapes, and the identification of these organisms is based in large part on the shape and structure of these silicate walls. Diatoms can be classified into two major groups: centric diatoms, which have radial symmetry (symmetry about a point) and pennate diatoms, which are bilaterally symmetrical (symmetry about a line).

Diatoms can be readily viewed using light and electron microscopy. Using a scanning electron microscope (SEM), you can view specimens that cannot be seen with the naked eye. Electron microscopes use electrons (instead of light as with light microscopes) to view the surface of the specimen. The surface image is formed from the electrons that bounce off the specimen and are recorded by the detector.

The following pages contain images (taken using a SEM) of the diatomaceous earth supplied in the FOSS "Mixtures and Solutions" kit.  Note that the images are magnified up to 3,500 times, resolving structures that are 15-50 microns in diameter (1 micron equals 1 millionth of a meter). Also, the particular sample of diatomaceous earth provided with our kit contained many types of diatoms, since you can see 4 or 5 different shapes.

Continue with SEM images of diatoms