What Karat is Pure Gold? A Gold Purity Complete Guide
Understanding What Karat is Pure Gold
What karat is pure gold? It’s a common question many gold owners have, whether they purchased, inherited, or were gifted their pieces. This guide will bring some answers to their questions.
We’ll clear up the confusion around karats, explaining why 24K stands out from the rest. Additionally, we’ll explain how purity connects to value, durability, and everyday use. By the end, readers will have a clearer understanding of the true worth of their gold.
In a nutshell:
24K gold is 99.9% pure gold and is mainly found in investment-grade bullion or coins. Lower karats of gold still contain pure gold, but they are an alloy of less expensive metals. Karats describe the percentage of pure gold in a piece of jewelry. The spot price of gold denotes the value of 24K gold and determines the value of all gold purchased and sold worldwide.
What is a Karat and How is Gold Purity Measured?
A karat is the unit used to measure the purity of gold, based on a simple 24-point scale. The higher the karat, the more gold content there is. On this scale, 24 out of 24 parts means pure gold. Lower numbers, therefore, mean lower gold content. A lower karat means that other metals, such as silver, copper, or nickel, have been mixed in.
For instance, 18K refers to 18 parts gold and 6 parts other metals. In percentage terms, 18K translates to 75% gold content (18/24). Each karat equals roughly 4.167% of the whole.
Later on, we’ll explain more clearly how this plays out with other karat ratings. But it goes without saying that understanding karats is key when dealing with gold. The karat number directly affects both its melt value and its resale price.
Historical roots of the karat system
In case you’re wondering, “Why 24?” The karat system’s link to gold purity goes back to the Middle Ages. At that time, they weighed gold coins using a 24-part standard of fineness.
A “mark” of gold was traditionally divided into 24 carats. (The term “carat” in this case comes from the carob seed, which they used as a standard for weighing precious metals.) The number of pure parts within that measure indicated the gold’s quality. The system worked well for trade, since 24 divides easily into halves, quarters, and other fractions.
By the time of the Roman and Byzantine empires, coins like the solidus had already reached a purity of nearly 24 carats. Over the centuries, the practice of measuring gold in 24 parts spread through Europe’s mints and goldsmith guilds. Eventually, it became a consistent way to guarantee authenticity.
Hallmarking practices and government standards later established the 24-karat scale as the global standard for gold purity.
The Purity of Pure Gold – 24 Karats
Pure gold is defined as 24 karats, meaning 24 out of 24 parts are gold with no other metals mixed in. In practice, 24K denotes gold as 99.9% pure. Achieving absolute 100% purity is nearly impossible outside of laboratory conditions.
Visually, 24K gold has a rich, solid, bright yellow color that stands apart from lower karats. It may feel counterintuitive, but pure gold is actually very soft, which makes it highly malleable. In other words, it’s easy to shape but also prone to bending and scratching.
For that reason, jewelers rarely use 24K for items meant for daily wear. Instead, one can see it in coins, bullion bars, and investment-grade pieces where purity matters more than durability.
Common Gold Karat Types and Their Purity Levels
Here’s a quick look at the most common karat ratings, how much pure gold each contains, and where you’ll most often see them used:
| Karat | Gold Purity (%) | Fineness | Description |
|---|---|---|---|
| 10K | 41.7% | 417 | Minimum standard for gold jewelry in the U.S.: durable and affordable, common in class rings and everyday wear. |
| 14K | 58.3% | 583 | Most popular in American engagement rings and fine jewelry, it strikes a balance between purity, strength, and cost. |
| 18K | 75% | 750 | Favored for high-end jewelry; richer color, higher gold content, and still durable for regular use. |
| 22K | 91.7% | 917 | Common in Indian, Middle Eastern, and Asian jewelry; valued for cultural traditions and deep yellow color, though softer. |
| 24K | 99.9% (pure) | 999 | Used mainly for investment pieces, such as coins and bullion, it is rarely used in everyday jewelry due to its softness. |
How to Determine Gold Purity in Your Items
In a previous article, we discussed several methods to tell if gold is real. Some of those same checks can also reveal not only authenticity but also purity. Here are a few of them:
Hallmark stamps
The simplest way to check the purity of gold is by reading the hallmark stamp on a gold item. These are tiny markings, typically found inside a ring band, on a clasp, or at the back of a pendant. The stamps denote the karat or fineness, but also sometimes the designer or country of origin.
For example, stamps might include fineness numbers such as 585 (which equals 14K, or 58.3% pure gold), 750 (18K, or 75% pure), or 999 (24K, essentially pure gold). In the U.S., the karat mark (like 10K, 14K, 18K, 24K) is also widely used.
If there isn’t a stamp, it doesn’t automatically mean the item isn’t gold. It may just be older or worn down. If that’s the case, use other methods of testing to determine purity.
Acid test
Acid test kits are a common way to get a rough idea of purity at home. They’re inexpensive, widely available, and don’t require professional equipment. Online stores or jewelry supply stores carry them.
The kit comes with small bottles of acid solutions marked by karat values, along with a testing stone. You gently scratch your gold piece on the stone to leave a mark, then apply a drop of acid. If the streak stays, your item is at least that karat. If it fades or dissolves, the gold is of a lower purity.
While useful, this test can leave small scratches on your item. It is also less accurate on plated items. So, this method works as a quick check rather than a final valuation.
Density test
Another simple method is the density test, which compares the weight of an item to its size. Pure gold has a density of approximately 19.3 g/cm³, so the closer your item measures to this value, the higher its purity.
To try this at home, you’ll need a precise scale and a container of water.
- Weigh your item in the air.
- Weigh it again while it’s suspended in water.
- Subtract the second weight from the first to find the item’s volume.
- Divide the weight in air by this volume to calculate density.
- Compare your result to standard densities for different karats:
- 24K ≈ 19.3 g/cm³
- 18K ≈ 15.6–16.5 g/cm³
- 14K ≈ 12.9–14.6 g/cm³
- 10K ≈ 11.6–12.9 g/cm³
One caveat: this method works best for solid gold items without gemstones or hollow parts. Stones, empty sections, or alloys with similar densities can skew the reading. It’s most reliable for plain gold pieces.
X-Ray fluorescence (XRF) test
An XRF test is one of the most accurate methods of testing gold purity without damaging the item. Jewelers and gold buyers often keep an XRF analyzer on hand. The device shines a beam of X-rays into the piece, and the machine measures how the atoms inside respond. From that, it produces a detailed breakdown of the piece’s composition.
Current Trends and Considerations When Selling Gold
Spot price
The spot price is the live, constantly changing market price of pure gold. It refers to 24K gold and is expressed in dollars per ounce (or gram, or kilo). Buyers often use this value as the benchmark. Checking the spot price before walking into a shop helps to know whether the offer presented is fair.
As a gold seller, it’s essential to note that most jewelers use 10K, 14K, or 18K gold to create jewelry. That means the value of these lower-karat pieces is only a percentage of the spot price.
For example, if the spot price of gold today hovered around $3,000 per ounce ($108 per gram), each karat would pay out like this:
- A 10K gold ring would be worth about 41.7% of the spot price, about $1,251 per ounce ($45 per gram)
- A 14K gold ring would be worth about 58.3% of the spot price, about $1,750 per ounce ($63 per gram)
- An 18K gold ring would be worth about 75% of the spot price, about $2,250 per ounce ($81 per gram)
Have gold to sell?
Request a free Alloy Appraisal Kit, ship from home, and receive a same-day offer after appraisal.
Have gold to sell?
Request a free Alloy Appraisal Kit, ship from home, and receive a same-day offer after appraisal.
As you can see, these percentages directly reflect the gold content in each karat. 10K contains 41.7% pure gold, 14K has 58.3%, and 18K carries 75%. The higher the purity, the larger the share of the spot price your jewelry will command.
The spot price fluctuates daily. A seller could receive more for their gold tomorrow than they do today. However, when selling a ring or two instead of a large lot, the difference usually isn’t significant. That’s because historically, gold prices have either held steady or climbed higher. So a few dollars up or down on the spot chart won’t meaningfully change the payout.
Wearability
Remember when we established earlier that most gold jewelry is 10K, 14K, or 18K? That’s not without reason. It’s because these karats are more suited for everyday wear than pure gold. For buyers who intend to use gold as jewelry, durability is just as important as purity.
Lower karat gold achieves durability by mixing with stronger metals, such as copper, nickel, or silver. This blend makes the piece less likely to bend or scratch. It also keeps the price more affordable because it contains less gold. Take 10K gold, for instance. It’s popular for everyday wear, such as rings or bracelets, due to its durability and affordability.
At the other end, 18K attracts buyers with larger budgets who want something close to pure gold, but strong enough for daily wear. And then there’s 14K gold, which sits right in the middle, balancing gold content with price.
In the Western world, people consider 24K gold too soft for everyday jewelry. Instead, it is found in bullion, coins, and other investment pieces. Investors value its purity above wearability. However, people in India, China, and the Middle East commonly wear jewelry made of 24K gold. It symbolizes wealth, status, and good fortune. It’s traditional to gift and wear it on significant life events, such as weddings and festivals.
Buyer comparison and gold price considerations
When selling gold, the karat rating of an item sets its starting value. Buyers calculate everything based on the melt value of pure 24K gold. However, the type of buyer selected determines how much of that karat-adjusted value a seller receives. Below is a side-by-side comparison of these buyers.
| Buyer Type | Do they care about karat? | Typical Payout | Speed | Safety & Transparency |
|---|---|---|---|---|
| Online Buyers | Yes. Online buyers pay based on melt value, and the karat rating is essential for calculating that. | 70–90% of melt value | Usually 1–3 days | High (video recording, and insured shipping included) |
| Local Jewelers | Yes. Local jewelers may resell or melt pieces, but in either case, they need to know the amount of real gold contained in the piece. | 40–60% of melt value | Same day | High (face-to-face transactions) |
| Pawn Shops | Yes. Pawn shops typically only offer value based on the gold content, rather than the design or brand. | 20–55% of melt value | Same day (Immediate) | Medium (you must check reviews first) |
| Collectors or Resale Buyers | Sometimes. Someone may value a branded, vintage, or designer piece more for its aesthetics or provenance than for its purity. | Varies widely | Varies | Low (possible scams and low-ball offers) |
As you can see, online buyers generally provide some of the best payouts. That’s mainly because they base their offers on melt value and don’t carry the same overhead costs as other buyers.
At The Alloy Market, we fall into this category – and we’re proud to offer some of the most competitive payouts in the market. See for yourself.
Gold Melt Value Calculator
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Final Thoughts on Pure Gold and Karat
The takeaway is simple: 24K equals pure gold. That number has been the global standard for centuries, serving as the benchmark seen everywhere, from bullion bars to wedding jewelry.
Knowing the karat level of a piece of gold isn’t just trivia. It determines melt value, resale potential, and even the durability of a piece if someone plans to wear it frequently. With that understanding of purity, one will have a clearer idea of their gold’s worth when the time comes to sell.
If you want to see how your gold items measure up, use Alloy Market’s gold calculator. It’ll help you stay informed, avoid surprises, and get the most out of your gold when selling.
Alloy Buys Gold
Do you have gold to sell? No matter the karat, Alloy Market wants to buy your gold. To get started, request a free Appraisal Kit. We’ll ship it right to your door right away.
Use the free, postage-paid parcel to safely ship your items to us for examination. We will conduct top-of-the-line testing to ensure the purity and weight of your piece and send you a detailed offer. When you accept the offer, we initiate payment the same day!
