It all starts when the molten crystal is placed in the 1,400°C furnace.
The furnace itself is made by expert potters using clay, so more in keeping with artisanal methods than industrial ones.
There shouldn’t be any cracks in the furnace chamber, as the melting process needs to take place under the best possible conditions.
These furnaces are not used for long, and after a few weeks they are replaced with new ones.
The crystal can then be worked between 24 and 48 hours after it comes out.