Abstract: The present invention relates to a method for manufacturing an exterior part for a timepiece or piece of jewelry made of Murano glass, said method comprising the following steps: providing a material formed of glass rods (2), also referred to as glass tubes, arranged side by side; multi-cycle heat treatment to consolidate the material and form a blank; machining the blank to produce the exterior part, the method being characterised in that the heat treatment comprises a first cycle (a) consisting of heating the material from a temperature less than or equal to 100° C. to a temperature between 450 and 650° C. at a heating rate between 4 and 12° C./min in order to avoid the formation of air bubbles during the manufacturing of the blank. It also relates to the exterior part for a timepiece or piece of jewelry, in particular a watch case, having a structure with few or no air bubbles.