24K or 24ct Gold

• Purity: 99.9% to 100% gold
• Properties: This is the purest form of gold, meaning it contains no other metals.
• Pros: Very rich yellow colour, high value, and hypoallergenic.
• Cons: Soft and malleable, so it's not ideal for daily wear items like rings or bracelets because it can easily be bent, scratched or dented.

22K or 22ct Gold

• Purity: 91.67% gold
• Properties: Very high purity with a rich yellow colour, but still somewhat durable.
• Pros: Retains the rich colour and is more durable than 24K gold.
• Cons: Slightly less pure than 24K, still fairly soft for everyday jewellery.

18K or 18ct Gold

• Purity: 75% gold
• Properties: This is one of the most popular choices for high-quality jewellery. It strikes a good balance between purity and durability.
• Pros: Great mix of gold content and strength, excellent for rings, necklaces, and bracelets. It’s still yellow in colour but less intense than 24K gold.
• Cons: Still softer than lower-karat gold and may not be suitable for very rough wear.

14K or 14ct Gold

·      Purity: 58.33% gold

• Properties: This gold alloy contains more copper, silver, or other metals, making it more durable.
• Pros: Highly durable, great for daily wear, more affordable than higher-karat gold.
• Cons: The colour is less intense and more muted compared to higher karats of gold, so it has a less "yellow" or "rich" gold look.

10K  or 10ct Gold

• Purity: 41.67% gold
• Properties: The minimum karat value that can still be called "gold" in the U.S. It’s primarily made up of other metals like copper and silver.
• Pros: Very durable and affordable
• Cons: The gold content is lower, meaning the colour can be more pale and not as "golden” or “yellow”

9K  or 9ct Gold (37.5% Gold)

• Purity: 41.67% gold
• Properties: The minimum karat value that can still be called "gold" in Australia. It’s primarily made up of other metals like copper and silver.
• Pros: Very durable and affordable.
• Cons: The gold content is low, meaning the colour is more pale and not as "golden”.

Other Considerations:

• Colour: The colour of gold can also vary with karat, especially in alloys mixed with different metals:
• Yellow Gold: Often used with copper and silver.
• White Gold: Mixed with metals like palladium, platinum or nickel for a silvery appearance.
• Rose Gold: Mixed with a higher amount of copper, giving it a reddish or pink hue.
• Durability: As you go lower in karat (like 10K or 14K), the gold is harder, making it more durable and scratch-resistant, but it contains less pure gold.

Reference: https://www.gold.org/about-gold/about-gold-jewellery