Humus

Transmitted Brightfield Illumination

The brown particle dominating this field would be placed in the humus category. It is Plant-derived
but is clearly part of the soil. On the lower left two diatoms are attached. Numerous mineral grains
are also adhering to the particle. Tapelifts from surfaces retain all this detail. Swab, wipe, or
vacuum samples destroy these associations and create artificial ones that have little diagnostic value.