Subgingival calculus is typically characterized by:

Subgingival calculus is primarily formed beneath the gumline and is often identified by its coloration. It typically has a black, brown, or dark green color due to the mineralization of bacteria and the presence of pigments from blood and other sources. This dark coloration can make it easier to differentiate from supragingival calculus, which is found above the gumline and can appear lighter in color.

The other options do not accurately reflect the characteristics of subgingival calculus. A chalky white appearance is more commonly associated with supragingival calculus that is primarily formed from saliva. A smooth and shiny texture is not typical for subgingival calculus, which can be rough due to its mineralized nature. Yellowish discoloration can also describe supragingival deposits or stains rather than the more mineralized, darker deposits that characterize subgingival calculus. Consequently, understanding these color and texture attributes crucially aids in the identification and management of periodontal disease.