Which statement best describes Weigert's hematoxylin?

• A. It uses iron as the mordant and is not aluminum-based
• B. It uses aluminum as the mordant
• C. It stains cytoplasm blue
• D. It requires acid-alcohol differentiation

Answer: (A)

Weigert's hematoxylin is defined by using iron as the mordant, forming an iron-hematoxylin complex that binds strongly to tissue structures and yields a blue-black nuclear stain. That iron-based mordant is what sets it apart from aluminum-based hematoxylins, so the best description is that it uses iron as the mordant and is not aluminum-based.

Nuclei are what hematoxylin stains best, producing the blue-to-black nuclear coloration, while cytoplasm is typically taken up by a counterstain (like eosin) rather than by hematoxylin itself, so staining the cytoplasm blue isn’t characteristic of this stain. Acid-alcohol differentiation is a procedural step that may or may not be used in different protocols, but it isn’t the defining feature of what distinguishes Weigert's hematoxylin.