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The least common method of analyzing crystalline silica is based in part on the differing Si-O bond strengths and densities of the various silicas compared to the silicate minerals. While the silicas are generally uncharged (except perhaps for SiO2 · x H2O), in silicate minerals the tetrahedra are polarized or negatively charged relative to the positive counter ions these minerals contain. These chemical differences affect the speed at which each mineral dissolves in certain acids, bases, or molten fluxes. This differential solubility is often slight so that chemical separation is sometimes incomplete. The separation is further complicated because the rate of dissolution is related to the surface-to-volume ratio; so small particles of the less soluble minerals sometimes dissolve faster than large particles of more soluble minerals. This is a good and inexpensive choice for samples that are well understood and contain either no interferences or ones that are not readily dissolved.

Analytical methods developed by recognized authorities provide a basis for individual laboratory procedures. A summary of and access to accepted methods is provided.
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