Alizarin Red S is used in histology and histopathology to stain, or locate calcium deposits in tissues.
In the presence of calcium, Alizarin Red S, binds to the calcium to form a Lake pigment that is orange to red in color.
Whole specimens can be stained with Alizarin Red S to show the distribution of bone, especially in developing embryos.
In living corals alizarin Red S has been used to mark daily growth layers.

In geology, Alizarin Red S is used on Thin sections, and polished surfaces to help identify carbonate minerals which stain at different rates.
Alizarin Red S is used in histology and histopathology to stain, or locate calcium deposits in tissues. In the presence of calcium, Alizarin Red S, binds to the calcium to form a Lake pigment that is orange to red in color. Whole specimens can be stained with Alizarin Red S to show the distribution of bone, especially in developing embryos. In living corals alizarin Red S has been used to mark daily growth layers. 
In geology, Alizarin Red S is used on Thin sections, and polished surfaces to help identify carbonate minerals which stain at different rates.
Alizarin Red S