Complex sentence: Gold and silver have no eutectic point, which means they can be alloyed together in any ratio, however, when silicon is added to aluminium they only blend together evenly on a molecular level up to approximately a 12% silicon content.
Split into simpler sentences: Gold and Silver have no eutectic point, which means they can be alloyed together in any ratio. However, when Silicon is added to Aluminum they will only blend together evenly on a molecular level up to approximately a 12% Silicon content.