Dosage
The maximum concentration of silicon that can be used without producing embrittlement depends strongly on the copper content and, therefore, also by definition on gold fineness and silver content. In a relatively copper-rich 18 ct alloy with 4.5% Ag, 18% Cu and 2.5% Zn, the maximum concentration of silicon is approximately 0.05% by weight. An addition of 0.1% Si causes complete embrittlement of the alloy. In contrast, 14 ct yellow alloys may contain approximately 0.04 to 0.08% silicon and 10 ct alloys can tolerate an even higher concentration of silicon due to their higher copper contents. Additions of 0.15% to 0.35% Si were found to have no detrimental effect.