Match

EPMA Probe

 

Standard Menu Details > Options

Match

This dialog is used to match a given standard or unknown composition to the standards in the standard database. Can be used to select the closest standard to an unknown sample for quantitative analysis or to suggest possible mineral identification.

 

The dialog will display the last selected standard as a default composition to match to. To match to an arbitrary unknown composition, click the Enter Unknown button and enter a compositional string in weight percent.

The routine automatically re-calculates all analyses in mole or atomic percents for the vector fit using a sum of the square of the differences algorithm. The following is an example of the output from the "match" command after entering a composition of 70.51% of FeO and 29.49% of SiO2 (fayalite) using the DHZ database :

 Unknown composition:

     fe      si                                                

    70.51   29.49     .00     .00     .00     .00     .00     .00

 Sum =   100.00

 STD =   5  Fayalite, East Greenland, p. 4           MATCH = 6.718   

 STD =   4  Fayalite, Pantelleria, p. 4              MATCH = 12.81   

 STD =  68  Grunerite, U.S.A., p. 151                MATCH = 30.25   

 STD =  50  Orthoferrosilite, p. 105                 MATCH = 34.24   

 STD = 183  Titaniferous magnetite, p. 427           MATCH = 38.97   

 

Once the list of sorted standards has been loaded (decreasing match vector) each standard may be viewed by simply double clicking it in the list. The output will be automatically directed to the log window.

To copy the list of standards matched to the Window clipboard, click the Copy to Clipboard button.

It may be most useful to open one of the supplied databases for matching an unknown composition depending on the circumstances. See the section on the File | Import menu.

More:

Weight Percent Entry