Carats vs Karats Explained: Understanding the Difference in Jewellery

When it comes to fine jewellery, the words carat and karat are often used interchangeably -yet they often refer to two very different things. If you’ve ever been confused by the difference, you’re not alone. Whether you’re shopping for a diamond engagement ring or looking for a gold wedding band to mark your special day, understanding these terms although is not essential, can be helpful.

At MDT DESIGN, we believe in educating our clients so they feel empowered and confident to make the right choice in what best suits them. In this entry, we will break down the difference between carats and karats, how they’re measured, and what they mean for your jewellery.

What Is a Carat?

Carat (ct) is a unit of weight used to measure diamonds and other gemstones. It tells you how much the stone weighs- not how physically big the stone looks.

✔ Quick Facts About Carats:

• 1 carat = 0.2 grams
• A diamond’s carat weight impacts its price significantly
• Two diamonds of the same carat weight can look to be a different size depending on how they’re cut, a deeper stone will hold more weight through the middle of the stone making it look smaller, while a stone that is shallower will tend to look larger. A perfect balance is key.

Carat weight is just one factor in a diamond’s value. A smaller diamond with exceptional cut, colour, and clarity can be more valuable than a larger diamond with lower specification. At MDT DESIGN, every diamond we select is carefully chosen not just for carat weight, but for overall beauty and brilliance.

What Is a Karat?

Karat (K or kt) is a unit that measures the purity of gold. Pure gold is 24 karats, meaning it is 100% gold with no other metals mixed in.

Because pure gold is soft and not ideal for everyday wear, for jewllery it is more often than not alloyed with other metals (like silver, copper, or palladium) to increase its strength, durability and to change the colour.

In Australia, gold purity is often stamped using ct (carat) instead of K or kt. For example, you may see 18ct, 14ct or 9ct inside a ring. In this context, ct refers to gold purity, not diamond weight.

This is where confusion can arise – because ct can refer to both gold purity and gemstone weight, depending on the context. When describing diamonds, ct almost always refers to carat weight. When stamped inside a ring, it usually refers to the purity of the gold.

✔ Common Gold Karat Types:

• 24K = 100% pure gold (rarely used in engagement rings)
• 22K = 91.7% gold
• 20K = 83.3% gold
• 18K = 75% gold – commonly used in fine jewellery like MDT DESIGN pieces
• 14K = 58.5% gold
• 9K = 37.5% gold – more affordable, but less rich in colour

💍 Why MDT DESIGN Uses 18ct Gold:

At MDT DESIGN, we craft our jewellery mostly in 18ct gold as it offers the perfect balance between purity and strength. It gives you that rich, luxurious gold tone while also standing up to everyday wear. It’s ideal for heirloom-quality pieces designed to last for generations.

Carat vs Karat: A Simple Breakdown

Why the Confusion?

It’s easy to see why people mix up carat and karat– they sound almost identical! To make things even more complicated, some regions (like the U.S.) spell gold purity as karat, while others (like Australia and the UK) commonly spell it carat as well. At MDT DESIGN, we use ct for gemstones and ct (not K) for gold, in line with Australian standards.

How These Affect Your Jewellery Choices

Choosing the Right Carat for a Diamond:

• A larger carat doesn’t always mean a better diamond. The focus needs to be also on the cut, clarity, and colour of the stone.
• Consider what size and shape look best on your hand. A well-cut 0.90ct stone can appear larger than a deep-cut 1.00ct.
• Our Ideal and Excellent cut diamonds ensure a perfect balance with the stone being as bright as possible.

Choosing the Right Karat for Gold:

• 18ct gold offers the best of both worlds-durable enough for everyday wear and rich in colour and purity.
• White, yellow, and rose gold are all available in 18ct at MDT DESIGN and can be chosen based on personal style and preference.

Final Thoughts

Understanding the difference between carats and karats empowers you to make more informed decisions when choosing fine jewellery. Whether you’re selecting a diamond for its sparkle or choosing a gold purity that suits your lifestyle, both carat and karat play vital roles in your jewellery’s beauty and value.

At MDT DESIGN, we take pride in educating our clients and crafting pieces by hand that meet the highest standards of quality. Whether you’re shopping for your dream engagement ring or refining your knowledge, we’re here to guide you every step of the way.

Continue your journey by exploring our guide to 18ct Gold and the 4 C’s of Diamonds.
Or visit our Melbourne showroom or contact us to view our handmade collections and discuss your dream jewellery with one of our experienced jewellers.

Frequently Asked Questions

Q: Can a diamond be high in carats but low in value?
Yes. A high carat diamond with a poor cut, clarity, or colour may not be as valuable or visually appealing as a smaller, high-quality stone.

Q: Is 24ct gold better than 18ct gold?
24ct gold is purer than 18ct gold but much softer, making it impractical for most jewellery. 18ct gold is more durable and still offers a rich, luxurious tone and finish.

Q: What diamond carat weight is best for an engagement ring?
It depends on your style and budget. Popular choices range from 0.50ct to 1.50ct, but at MDT DESIGN, we custom-make each ring to suit your vision perfectly.

Q: Is 9ct gold real gold?
Yes, but it contains only 37.5% gold and it has a much lighter colour tone than more pure gold pieces.

Q: Do all precious gemstones use carats to measure size?
Yes, carats measure the weight of most gemstones, but the appearance of size varies depending on the density and cut of each stone.