Describe the appearance of a Datum Identification Symbol.

The appearance of a Datum Identification Symbol is characterized by a datum letter enclosed within a rectangular box. This symbol indicates the reference point or feature from which other measurements or tolerances are derived, making it a crucial part of Geometric Dimensioning and Tolerancing (GD&T). The rectangular box helps distinguish the datum letter visually from other annotations and dimensions on the drawing, facilitating clear communication of design intent.

The use of letters for datums (such as A, B, C) allows engineers and manufacturers to establish a standard reference frame, helping to ensure consistency across parts and assemblies. Proper identification and documentation of datums are necessary for effective manufacturing and inspection processes since they serve as the basis for aligning and measuring other features of the part.