Figure 7. Cross-polarized light view of the same field as that in Figure 6. Clicking on the “PPL/XPL” button has brought up this cross-polarized light view. Subsequent click on the same button brings back the plane polarized light view (Figure 6). Click on “History” button to view ‘Previous Pages’ window ((Figure 8). Click on “Search” button to view ‘Search Sandstone Petrology’ window (Figure 9).