Compass Card

The rose is of the same type as NG-MC-877-B, but the cap is fitted with a gemstone, presumably agate with a hole for the pen at the bottom: the rotation of the rose was improved by the materials used, while the swaying was reduced by increasing the friction surface of the gemstone. The rose can be rotated within an outer rim, on which a scale in degrees per quadrant is applied; this was to compensate for magnetic variation (the angle between true north and magnetic north).