After this, the surface to be stained needs to be polished only enough to remove any grooves made by the saw blade. We used 220 grit carborundum on a rotary lap, wheel to do this. After this wash off the slab thoroughly in tap water, no detergents, and allow it to dry. Now you should prepare a laboratory site where the staining can take place and where you can mix the staining solutions. It is recommended that the staining be accomplished beneath a fume hood because the acids used are caustic.
Good ventilation is necessary.
We were able to use the college chemistry laboratory for this. The staining process involves the use of three chemicals. After that Amaranth is used to stain the plagioclase on that surface a red color. Then Cobaltinitrite is used to stain any K-feldspar on that surface a yellow color. The ideal arrangement is to use two adjoining fume hoods.