What Is Gold Fineness?

The American Gold Eagle is .9167 fine, while the American Gold Buffalo is struck at .9999 fine, which is 99.99% pure gold. Investors buy both every single day, and that gap confuses a lot of first-time buyers.

So, what is gold fineness? It’s the purity of gold in a coin or bar, written as a proportion and measured in parts per thousand.

This post covers how fineness works, how gold purity converts to karat and percentage, what fineness an IRA requires, and why a higher number isn’t always the better buy.

Gold fineness, defined

Fineness is the share of pure metal in a piece, expressed out of 1,000. A coin marked .999 is 999 parts gold and one part other metals. A coin marked .9999 is 99.99% pure gold, with only trace impurities left behind.

You’ll see the mark stamped right on the metal. Look at a gold coin from the Royal Canadian Mint or the Perth Mint, and you’ll find “9999” pressed into the design. That figure is the fineness, and it tells you the proportion of fine gold in the total weight of the gold item.

This is the millesimal fineness system, and expressing fineness in parts per thousand is the modern standard for precious metals. It’s more precise than the older karat system, which only divides gold into 24 parts.

The London Bullion Market Association, the body that sets the global standard for gold bars, won’t accept a bar onto its Good Delivery list below .995.

Fineness vs. karat vs. purity percentage

Karat, fineness, and percentage all measure how much of the metal is gold. Gold purity is commonly measured in these three ways, and all of them are used to measure gold purity on a different scale.

Karat (sometimes spelled carat outside the United States) runs out of 24, so 24K gold is as pure as it gets. Fineness runs out of 1,000 and shows up as a three-figure number like .750. Percentage is the plain version most people picture.

Here’s what the three measure:

Karat	Fineness	Purity	Typical use
24K	.999 to .9999	99.9% to 99.99%	Investment bullion
22K	.9167	91.67%	Gold Eagle, Krugerrand
18K	.750	75%	Fine jewelry
14K	.585	58.5%	Everyday jewelry

A jeweler who says “18 karat” and a mint that says “.750” are describing the same purity of gold. The lower the number, the more alloy metals are mixed in, which is the difference between 24 karat gold and the karat gold used in most jewelry.

Common gold fineness levels and what they mean

These purity levels cover almost everything you’ll run into as a buyer.

• Four nines fine (.9999): Investment bullion at its purest. The Gold Buffalo and the Canadian Maple Leaf both reach this level, and the Royal Mint and Perth Mint strike bullion coins to it as well.
• Three nines (.999): The standard for most modern bullion bars and many coins, including some commemorative pieces.
• Twenty-two karat (.9167): The American Gold Eagle and the historic South African Krugerrand. The alloy is usually copper, added to make the coin harder.
• Eighteen and fourteen karat (.750 and below): This is a level for modern jewelry. The alloy gives the metal its strength and its colors, like rose gold and white gold.

Note that gold-plated items are not solid gold at all. They’re a thin layer of gold over base metals, so their fineness applies only to that coating, not the whole piece.

Silver fineness

Silver follows the same logic. Fine silver is .999, and the purest silver bullion reaches .9999, the same four nines you see on the best gold. The other precious metals are measured this way too.

What fineness does gold need to be for a Gold IRA?

The IRS sets a legal minimum fineness for any metal held inside a precious metals IRA. Miss the number and the coin or bar doesn’t qualify for investment purposes inside the account, no matter how nice it looks.

Metal	Minimum fineness for an IRA
Gold	.995 (American Eagle allowed at .9167)
Silver	.999
Platinum	.9995
Palladium	.9995

The American Gold Eagle is approved at .9167 fineness, even though that’s below the .995 gold minimum, because the Eagle is a U.S. Mint coin written into the law by name.

Does higher fineness mean a better investment?

No. A higher purity number doesn’t automatically make a coin a better buy.

A .9999 Buffalo and a .9167 Eagle can each hold exactly one troy ounce of pure gold. The difference is the alloy, not the gold content, so the intrinsic value tied to the metal is the same, and you’re paying for the same amount of gold either way.

There’s even a tradeoff that runs the other direction. The 22-karat alloy in an Eagle or a Krugerrand gives the coin more durability, so it resists nicks and scratches better than a soft .9999 coin that can mark if you look at it wrong. For a coin that may change hands over the years, that hardness has real value.

What really drives what your gold is worth is the amount of fine gold inside, the recognition of the mint that produced it, how easy it is to sell against the spot price, and the premium you pay over that market price.

Why investors choose Swiss America

Fineness, karat, IRA rules, and which coin fits your goal. There’s a lot to sort out, especially on a first purchase. At Swiss America, you work with a named account executive who answers your questions and helps you choose what to buy. We’ve spent decades helping everyday investors buy gold and silver, so the first conversation usually starts with what you want to know.

To learn more about which coins or bars fit your goals, connect with the Swiss America team today!

Gold fineness: FAQs

What is the fineness of gold?

Gold fineness is the purity of gold stated in parts per thousand. A mark of .999 means the piece is 999 parts gold out of 1,000, or 99.9% pure.

• The scale: Fineness runs from 0 to 1,000, where 1,000 would be perfectly pure metal with nothing else in it.
• On the coin: Modern bullion carries the figure stamped on its face, such as “9999” on a Maple Leaf or “999.9” on a bar.
• Common terms: Karat and fineness are the two common terms you’ll see, and both measure how much gold is really there.

What does 999.9 gold fineness mean?

It means the gold is 99.99% pure, often called four nines fine. Out of every 10,000 parts, 9,999 are pure gold and only one part is anything else.

• The purest standard: This is about as refined as investment gold gets. The Gold Buffalo and the Royal Canadian Mint Maple Leaf are both .9999.
• Versus .999: The step from .999 to .9999 is tiny in practice. Both trade as pure, investment-grade gold.
• Softness: Higher purity also means a softer coin, so four-nines pieces scratch more easily than alloyed ones.

What’s the difference between gold fineness and karat?

They measure the same purity on different scales. The karat system divides gold into 24 parts; the millesimal fineness system divides it into 1,000.

• Quick conversion: 24K is about .999, 22K is .9167, 18K is .750, and 14K is .585.
• Where each is used: Jewelry tends to use karat, while bullion coins and gold bars use fineness.
• Same metal: A 22-karat coin and a .9167 coin are identical in purity. The two numbers are just two ways to measure gold.

What fineness of gold is allowed in an IRA?

Gold has to be at least .995 fine to qualify for a precious metals IRA, with the American Gold Eagle allowed as a written exception at .9167.

• The thresholds: Fine silver needs .999, while platinum and palladium each need .9995 to be eligible.
• The Eagle exception: The Gold Eagle is named in the law, so it qualifies despite its 22-karat content.

The information in this post is for informational purposes only and should not be considered tax or legal advice. Please consult with your own tax professionals before making any decisions or taking action based on this information.