Which of the following is NOT a characteristic used to classify a contact?

The classification of a contact in the context of Mineman (MN) generally relies on specific characteristics that help in identifying and differentiating contacts. Characteristics such as shadow, shape, and aspect change are vital as they provide critical information about the contact's size, silhouette, and how it might appear from various angles or distances.

Shadow refers to the outline or projection of the contact that can reveal its size and may be influenced by lighting conditions. Shape is fundamental in distinguishing contacts as different objects will have distinctive silhouettes. Aspect change involves how the contact's appearance transforms when observed from different viewpoints or when affected by environmental factors.

Color, while a notable attribute in many contexts, is not typically a primary characteristic for classifying contacts in this particular field. This is because color can vary significantly due to numerous factors such as lighting, weather conditions, or the object's material, making it less reliable for identifying or classifying contacts effectively. Thus, color is the characteristic that stands apart from the others mentioned, which are more consistently utilized in classification processes.