Goharshad Mosque is a former free standing mosque in Mashhad of the Razavi Khorasan Province, Iran, which now serves as one of the prayer halls within the Imam Reza shrine complex.

The first and the greatest surviving, Persian monument of the fifteenth century is the beautiful mosque of Gawhar Shad (1418) now abutting the shrine of the Imam Reza in Mashhad. Its portal continues the Samarkand style of arch within arch, enriched by a succession of bevels and reveals that give it depth and power. The thick, tower-like minarets, merging with the outer corners of the portal screen, extend to the ground and, together with the high foundation revetment of marble, give the ensemble the impression of solidity necessary to support its exuberant colour. The entire court façade is faced with enamel brick and mosaic faience of the finest quality.
The full scale of colours includes a dominant cobalt blue and turquoise, white, a transparent green, yellow, saffron, aubergine and mirror black – all tones fluctuating through several shades. The patterns lucid and vigorous, are artfully adapted to their decorative role, whether for eye-panels, or dome ornament meant to be effective at a thousand feet. Monotony, difficult to avoid in such a large area, and a distracting intricacy that might compete with the essential architectural forms are both forestalled.
This is accomplished by the energy of the faience floral patterns and brick geometrical schemes; by the emphatic rhythm of the arcades, open galleries and deep recesses; and especially by the contrast of the iwans.