A ghanta is cast bronze or brass, produced in the same Newari and Tibetan metalworking workshops that cast the vajra it is always paired with, and its proportions, the shape of the handle, the profile of the bell, are specified in ritual texts rather than left to a founder's taste.
Construction detail
The handle is commonly cast as half a vajra or, in more elaborate examples, topped with the face of a specific deity such as Prajnaparamita, and the interior of the bell is sometimes engraved with mantra syllables not meant to be visible once the bell is in regular use. Because vajra and bell are cast to be used as a matched pair, a serious practitioner's set is typically acquired or commissioned together rather than assembled from mismatched pieces.
Use and repair
In ritual use the ghanta is held in the left hand while the vajra is held in the right, rung at specific points during a recitation rather than continuously, a division of the two hands that mirrors the same pairing of wisdom and method the implements are said to represent. A cracked or dulled bell is not simply thrown away, since bronze can be re-melted and recast respectfully into a new implement by the same workshops that made the original, treating the metal as reusable even when the specific bell is not repairable.