Question

locating information in difficult graphics
approximate colors of jewelry alloys (ternary plot with gold (au), silver (ag), copper (cu))
a jewelry maker uses different combinations of alloys to change the appearance of jewelry.
which alloy combination would produce jewelry that is pale greenish-yellow?

• 30% copper, 20% silver, and 50% gold
• 10% copper, 40% silver, and 50% gold
• 60% copper, 20% silver, and 20% gold
• 20% copper, 10% silver, and 70% gold

Explanation:

To determine the alloy combination for pale greenish - yellow jewelry, we analyze the ternary diagram (for Gold - Silver - Copper alloys) and the given options:

1. For the option "30% copper, 20% silver, and 50% gold": Calculate the weight percentages. Copper (Cu) is 30%, Silver (Ag) is 20%, Gold (Au) is 50%. From the diagram, this composition is in the "Yellow" region, not "Pale greenish - yellow".

1. For the option "10% copper, 40% silver, and 50% gold": Cu = 10%, Ag = 40%, Au = 50%. Looking at the diagram, the "Pale greenish - yellow" region has relatively higher silver (Ag) and lower copper (Cu) compared to the "Yellow" region, and this composition fits the "Pale greenish - yellow" region.

1. For the option "60% copper, 20% silver, and 20% gold": Cu = 60%, Ag = 20%, Au = 20%. This composition is in the "Reddish" or "Copper red" region (due to high copper content), not "Pale greenish - yellow".

1. For the option "20% copper, 10% silver, and 70% gold": Cu = 20%, Ag = 10%, Au = 70%. This composition is in the "Yellow" region (closer to the gold vertex), not "Pale greenish - yellow".

Answer:

10% copper, 40% silver, and 50% gold