Table Gauge is a transparent measuring device divided into millimeters and tenths of a millimeter, used to measure which feature?

• A. The diamond's table.
• B. The girdle thickness.
• C. The overall diameter.
• D. The depth of the pavilion.

Answer: (A)

Measuring the width of the table facet—the large flat top of a cut diamond—is what a table gauge is designed for. The table is the flat surface you see on the crown, and its size, relative to the diamond’s overall diameter, is a key factor in how light is reflected and returned. The table gauge is transparent and graduated in millimeters and tenths, so you can place it across the table and read its width precisely to 0.1 mm. That measurement is then used to calculate the table percentage, which helps assess cut quality.

This tool isn’t used for girdle thickness, which is measured around the diamond’s edge with other calipers; nor is it used for the overall diameter, which spans from girdle edge to girdle edge, or for the depth of the pavilion, which is a vertical measurement from the table down into the pavilion.