But when the lake dries out, the sodium compounds are left behind. Crystals of salt are soft and easily scratched. They are mostly white, although they may be tinged with orange if they have some iron staining. Minerals dissolved in water are left behind when itevaporates, leaving salt deposits. These contain a variety of compounds, but they are usually dominated by sodium chloride.
Salt deposits are common in most deserts and also in salt marshes near estuaries.