After working the gold bar with the rolling mills, we have to anneal the gold in order to soften the gold, so that we can continue to work the gold. Over working the gold can cause to the gold cracking during manufacture, or at a later date in wear.
We have to gently heat the gold until cherry red in colour, and maintain this colour for around 30 seconds, this temperature is also close to melting point so it is very important to get this stage correct or we will be starting again.