The invention relates to an apparatus and a method for low-
contamination melting of high-purity, aggressive and / or high-melting glass or glass-
ceramic. According to the invention, for this purpose a melt is heated in a 
crucible or melting 
skull crucible by means of high-frequency 
radiation and is mixed or homogenized in the melting 
crucible. It is preferable for a gas 
nozzle, from which gas bubbles, e.g. 
oxygen bubbles (known as O2 bubbling), escape into the melt, to be provided at the base of the crucible. This alone makes it possible to achieve surprising multiple benefits in the melting 
skull crucible. Firstly, unmelted batch which drops into the melt in 
solid form, for example from above, is melted down more quickly as a result of more intensive mixing with the 
liquid fraction of the melt, secondly the temperature distribution in the melt is made more even, thirdly a uniform distribution or mixing of different glass constituents is achieved, and fourthly the 
redox state of the glass can be adjusted.