within the mica group. its approximate chemical formula is k(mg, fe) alsi o (f, oh) . this mineral is usually dark green to brown or black. it can be transparent to opaque, has a vitreous to pearly luster, and a gray-white streak. when weathered, its crystals appear sparkly yellow and are sometimes...
enforcement policy, guidance and publications radiation information for technical users and the regulated community find more on epa's air website . compliance and enforcement enforcement: policy, guidance & publications find more on epa's the compliance & enforcement websites pesticides and toxic substances...