WinHolclas, a Windows program for hollandite-supergroup minerals

Abstract

A Microsoft® Visual Basic software, WinHolclas, has been developed to calculate the chemical formulas of hollandite-supergroup minerals based on data obtained from wet-chemical and electron-microprobe analyses. WinHolclas currently evaluates 12 valid mineral species using the Commission on New Minerals, Nomenclature and Classification (CNMMC) of the International Mineralogical Association (IMA) nomenclature scheme for the hollandite-supergroup minerals, with the simplified general formula (A+, A2+)(M4+, M3+)8O16 in the coronadite and priderite groups. The program recalculates and estimates the chemical formulas of hollandite-supergroup species based on 16 oxygen atoms, with the option of octahedral site total of 8.00 atoms per formula unit normalization. Mineral compositions of the hollandite-supergroup are calculated based on the dominant tetravalent sixfold-coordinated cation, considering the dominant tunnel cation (A+, A2+) and the dominant charge-compensating octahedral cation (M3+, M2+). WinHolclas operates in four stages: (1) it estimates cation and anion contents provided by input chemical data; (2) it determines the dominant tunnel and charge-compensating cation in each group; (3) it assigns the hollandite-supergroup minerals to one of the two groups; and (4) it classifies the hollandite-supergroup species into an appropriate groups such as coronadite and priderite. WinHolclas allows users to: (1) enter up to 42 input variables for mineral-chemical analyses; (2) type and load multiple hollandite-supergroup mineral compositions in the data entry section; (3) edit and load the Microsoft® Excel files used in calculating, classifying, and naming the hollandite-supergroup minerals, and (4) store all the calculated parameters in the output of a Microsoft® Excel file for further data evaluations. The program is distributed as a self-extracting setup file, including the necessary support files used by the program, a help file, and representative sample data files.