Use one lamp and move the crystal under it. A flat crystal throws a broad reflection. A domed crystal bends that reflection into a curve that travels as you turn the case. Pits show up as tiny dark points in the reflection. On the lug, a polished bevel should carry the lamp as one continuous line. A break in the line is a knock that was buffed on one side only. You do not need a loupe. You need the lamp and a slow turn. Write the surface as you see it. Do not convert the observation into a grade, and do not compare it to a piece in a display box.

How it differs

For the Cartier Santos 39 8 Mm, compare the diameter you can measure with the length from lug tip to lug tip. A wide bezel can make the dial look smaller than the case. Keep the comparison inside this case idea.

Common mods

On the Cartier Santos 39 8 Mm, people change the insert, the bracelet, or the hand set. Name the one part that was changed and leave the rest undescribed rather than guessing.

What to check on a used piece

Check the clasp position, the end-link gap, and whether the hands pass cleanly on the Cartier Santos 39 8 Mm. Write those three and ignore the sales line. These notes are not authentication and not a shop.

A library page is written by {Site}. A photo post is one person’s notes. Neither authenticates a watch, offers it for sale, or speaks for the name on the dial.