Malachite green result. Numerous niche applications exploit the intense color of MG. It is used as a biological stain for microscopic analysis of cell biology and tissue samples. In the Gimenez staining method, basic fuchsin stains bacteria red or magenta, and malachite green is used as a blue-green counterstain. Malachite green is also used in endospore staining, since it can directly stain endospores within bacterial cells; here a safranin counterstain is often used. Malachite green can also be used as a saturable absorber in dye lasers, or as a pH indicator between pH 0.2–1.8. However, this use is relatively rare. Leuco-malachite green
Mineral petrography), it may become transparent even if that property is not seen in a hand sample. In contrast, some minerals, such as hematite or pyrite, are opaque even in thin-section. Colour is the most obvious property of a mineral, but it is often non-diagnostic. It is caused by electromagnetic radiation interacting with electrons (except in the case of incandescence, which does not apply to minerals). Two broad classes of elements (idiochromatic and allochromatic) are defined with regards to their contribution to a mineral's colour: Idiochromatic elements are essential to a mineral's composition; their contribution to a mineral's colour is diagnostic.