The use of the light microscope allows the viewing of samples at magnifications of up to 1,000 times, often with little or no sample preparation. A sample may be viewed as is, while noting properties such as color, transparency and morphology.
Because the sample is not isolated from the microscopist, it can be probed and manipulated in order to judge physical properties such as hardness and elasticity. In “microchemical testing” standard qualitative chemical tests are applied in miniaturized format to determine sample composition.
Specialized observational and illumination techniques allow the precise measurement of optical properties of transparent materials.
Polarized light microscopy (PLM) can determine optical properties that uniquely identify specific chemical phases.
In fluorescence microscopy the sample is illuminated by ultraviolet light causing some phases to give off visible light. The resulting spectrum is used to identify the sample.