Sphalerite ZnS ( primary ) alters to secondary hemimorphite Zn 4 Si 2 O 7 ( OH ) 2 . H 2 O, smithsonite ZnCO 3 and manganese-bearing willemite Zn 2 SiO 4.
22.
It is also one of the few mines in the world which mines " zinc oxides ", which actually is a mixture of non sulphidic zinc minerals such as smithsonite, hydrozincite, tarbuttite and willemite.
23.
It has been replaced by smithsonite and hemimorphite in order to distinguish it from the pinkish mixture of zinc oxide ( ZnO ) and iron ( III ) oxide ( Fe 2 O 3 ) used in calamine lotion.
24.
Other natural materials occasionally confused with or used in lieu of turquoise include : variscite and faustite; chrysocolla ( especially when impregnating quartz ); lazulite; smithsonite; hemimorphite; wardite; and a fossil bone or tooth called odontolite or " bone turquoise ", coloured blue naturally by the mineral vivianite.
25.
Many carbonates occur there, including ankerite Ca ( Fe, Mg ) ( CO 3 ) 2, barytocalcite BaCa ( CO 3 ) 2, calcite CaCO 3, siderite FeCO 3, smithsonite ZnCO 3 and witherite BaCO 3, as well as the non-carbonate minerals fluorite CaF 2 and baryte BaSO 4.
26.
You'll learn about the selenite caves of Mexico, where crystals of the mineral grow to 2 feet, and about a collecting trip to the deserts of Morocco, source of choice speci mens of vanadinite, smithsonite, azurite, malachite, cerussite and agates abound ( if you recognize all these, this mag's for you ).
