Muqarnas is "suspended ornamental vaulting, also called “stalactite” vaults; usually concave and arched but sometimes rendered as flat niches."1 At Humayun's Tomb, muqarnas of various styles can be found in the top of the iwans, around the dome's drum, above the corner niches on the plinth, and around the ceilings inside the tomb.
Muqarnas is a very prominent feature of the Gur i-Amir, the mausoleum of Timur in Samarkand, Uzbekistan. The tactile red, white, and blue ring of muqarnas around the ceiling of the entrance chamber of Humayun's Tomb is of the same star and niche pattern as muqarnas in a niche inside of the Gur i-Amir.
The muqarnas around the dome's drum and above the plinth's corner niches are like rows of small decorative brackets. With the exception of the ring of muqarnas in the entrance chamber that shares its pattern with muqarnas from the Gur i Amir, the muqarnas around the chamber ceilings inside the mausoleum are shallow white niches with red outlines.
The most noticeable muqarnas on the exterior of the mausoleum is in the top of the tomb's iwans, and it is monochromatic masonry that has the same pattern as the muqarnas inside the tomb.
1. D. Fairchild Ruggles, Islamic Gardens and Landscapes (Philadelphia: The University of Pennsylvania Press, 2008), 226.
Dadkhah, Negin, Hadi Safaeipour, and Gholamhossein Memarian. "Traditional Complex Modularity in Islamic and Persian Architecture: Interpretations in Muqarnas and Patkâné Crafts, Focusing on their Prefabricated Essence." In Offsite: Theory and Practice of Architectural Production ACSA Fall Conference Proceedings, edited by John Quale, Rashida Ng, and Ryan E. Smith, 130-38. Washington D.C.: Temple University, 2012.
Hillenbrand, Robert. "Aspects of Timurid Architecture in Central Asia." In Utrecht Papers on Central Asia: Proceedings of the First European Seminar of Central Asian Studies held at Utrecht, 16-18 December 1985, edited by M. Van Damme and H. Boeschoten, 255-86. Utrect: Institute of Oriental Languages, University of Utrecht, 1987.
Petersen, Andrew. Dictionary of Islamic architecture. London; New York: Routledge, 1996.