|   | PbClFThis sample of matlockite is displayed in the Smithsonian Museum of Natural History. Matlockite is a compound  of lead  with chlorine and fluorine. It has the composition PbClF.  The sample at left is about 8 cm across and is from Matlock, Derby, England. It is described as matlockite with galena. Matlockite is usually colorless to light yellow.   |