Mineral form of sodium chloride.
1Soluble minerals like halite can't be washed, but should be rinsed with alcohol.
2They include sulfur, graphite (the "lead" in pencils), gypsum, halite (rock salt), borax, talc, asbestos and quartz.
3Gold, jasper, uncut diamond, quartz (violet in color), halite (Carlsbad N.M.), calcite (S. Dakota), copper, turquoise (brilliant color)