Minerals in space group 129

Matlockite is a rare lead halide mineral, named after the town of Matlock in Derbyshire, England, where it was first discovered in a nearby mine. Matlockite (chemical formula: PbFCl) gives its name to the matlockite group which consists of rare minerals of a similar structure.

Litharge (from Greek , 'stone' + 'silver' ) is one of the natural mineral forms of lead(II) oxide, PbO. Litharge is a secondary mineral which forms from the oxidation of galena ores. It forms as coatings and encrustations with internal tetragonal crystal structure. It is dimorphous with the yellow orthorhombic form massicot. It forms soft (Mohs hardness of 2), red, greasy-appearing crusts with a very high specific gravity of 9.14–9.35. PbO may be prepared by heating lead metal in air at approximately 600 °C (lead melts at only 300 °C). At this temperature it is also the end product o

Bismoclite is a bismuth oxohalide mineral with formula BiOCl. It is the naturally occurring form of bismuth oxychloride. The name was derived from its chemical constituents. It is a secondary bismuth mineral first thought to be composed of bismuthyl ions (BiO+) and chloride anions, however, the existence of the diatomic bismuthyl ion is doubtful.

Mackinawite ( ) is an iron sulfide mineral, which can contain nickel substituting for iron(II), with as chemical formula (where x = 0 to 0.11). As indicated by its chemical composition, Fe(1+×), Fe is present with an excess of × over S, and it is thus an iron-rich, or a sulfur-deficient, iron monosulfide mineral. The mineral crystallizes in the tetragonal crystal system and has been described as a distorted, close packed, cubic array of S atoms with some of the gaps filled with Fe. Mackinawite occurs as opaque bronze to grey-white tabular crystals and anhedral masses. It has a Mohs hardness of

thumb | right Daubréeite is a rare bismuth oxohalide mineral with formula . It is a creamy-white to yellow-brown, soft, earthy clay–like mineral which crystallizes in the tetragonal crystal system. It is a member of the matlockite group.