Question

You’re looking to purchase a gold ring, but you know that gold is extremely malleable (i.e., too soft). How can you make this stronger? Will this still be considered 24 karat gold? How will the optical properties (i.e., color) change? If you add another element, how much and where will the atoms resided?

Answer 1

• You’re looking to purchase a gold ring, but you know that gold is extremely malleable (i.e., too soft). How can you make this stronger?

By preparing its alloy, gold can be made stronger. Generally, copper or silver and sometimes zinc are used for preparing the alloy.

• Will this still be considered 24 karat gold?

‘Karatage’ is the measurement of purity of gold alloyed with other metals.

24 carat is pure gold with no other metals.

Less karatages contain less gold; for example, 18 karat gold contains 75 per cent gold and 25 per cent other metals, often copper or silver.

• How will the optical properties (i.e., color) change?

Color of Gold                         Alloy Composition

Yellow Gold (22K)                 Gold 91.67%

Silver 5%

Copper 2%

Zinc 1.33%

Red Gold (18K)                      Gold 75%

Copper 25%

Rose Gold (18K)                    Gold 75%

Copper 22.25%

Silver 2.75%

Pink Gold (18K)                     Gold 75%

Copper 20%

Silver 5%

White Gold (18K)                   Gold 75%

Platinum or Palladium 25%

• If you add another element, how much and where will the atoms resided?

The unit cell for an alloy of gold and copper has gold atoms at the corners and copper atoms at the face sites.