Enamel is glass fused to a metal surface at high temperatures. The glass is a blend of silica, soda, lime, and borax, creating a clear colorless product known as flux. Enamel can be transparent, opaque or translucent, with a vast range of colours achieved by adding metal oxides to the powdered flux. Vitreous enamel is utilized to add colour to jewelry by filling in specific areas and firing at high temperatures, fusing the glass to the metal. This process is both an art and a science, requiring multiple applications and firings to achieve the desired depth of colour and translucency. Each colour is fired at a different temperature and duration, requiring the enameller to know the precise glass powder and metal oxides mixtures for every colour, the firing temperatures and the amount of time the object has to remain in the kiln.

Vitreous enamel is incredibly versatile and can be applied using various techniques. It can be diluted and painted, it can be made into a thick paste and filled into wire compartments as in cloisonné or filled into engraved hollows as done in champlevé or applied into cells with no backing so that the light shines through, known as plique à jour.

Enamellers relied on glass-makers for their supplies. The island of Murano, near Venice, was the principal source of raw enamel glass, and it is likely that the early material used in Indian enamel came from Europe via the global trade in luxury goods. In 1617 Sir Thomas Roe recorded in his diary that the Portuguese had, over the previous two years, brought enamel from Goa to Agra, presumably to sell to the Mughal karkhanas. Red enamel was sold at forty-five shillings an ounce, and blue, white, and green at eighteen shillings an ounce.
When working with gemstone-set pieces, it is essential to complete enamel work before setting, as firing after setting may cause the kundan to melt and the gemstone to fall out.