If a dealer quoted you different amounts for your box of gold jewelry with different stamps on each piece, it is because of the karat mark on each piece. Gold purity determines exactly how much of a piece's weight is actual gold, and that number determines every offer you will receive at any gold buyer's office in New York City and beyond. This article explains the purity levels in gold to give you an idea of what you are dealing with before entering a deal with a buyer.
How the Karat System Measures Gold Purity
Pure gold is too soft for everyday jewelry. As a result, manufacturers mix it with other metals like copper, silver, zinc, or nickel, depending on the desired color and strength. The karat stamp tells you how much of the finished piece is pure gold, measured in parts per 24. An 18K piece contains 18 parts gold and 6 parts alloy, which equals 75% pure gold by weight.
Gold does not lose purity through age, wear, or tarnish, so the ratio remains permanent. A 14K ring from 1960 has the same gold purity as one made last month. The stamp is fixed information, and it is the first number any reputable Manhattan gold dealer uses to calculate your offer.
What Each Karat Mark Actually Means
10K is 41.7% pure gold. It is the legal minimum karat for jewelry sold as gold in the United States and frequently appears in fashion pieces, college rings, and mass-market items. The alloy content is high, which makes 10K harder and more scratch-resistant, but the gold purity percentage is the lowest you will encounter at a dealer.
14K is 58.3% pure gold and the most common karat in American jewelry. The majority of the jewelry lots that come into AGR Gold's Diamond District office are 14K. US manufacturers have favored it for decades because it holds real value while staying durable enough for daily wear. If you have a mixed lot of American jewelry and are unsure of the karats, most of it is probably 14K.
18K is 75% pure gold and the standard for high-end and European jewelry. Cartier, Van Cleef, Tiffany, and some other pieces are 18K. At the same weight, an 18K piece contains more gold than a 14K piece, and that gap shows up directly in the offer.
22K is 91.7% pure gold. This karat gold is rarely used in jewelry made in the United States. However, estate collections in Manhattan frequently include 22K pieces originating from Indian, Middle Eastern, and South Asian families. These pieces tend to be heavier, with a deeper yellow color, and their gold purity makes them among the most valuable pieces by weight that come in for evaluation.
24K is 99.9% pure gold and is almost never used in jewelry because of its softness. When you encounter a 24K stamp, it is typically on a bullion coin or investment bar. Pieces labeled 24K that appear to be wearable jewelry are worth testing carefully, particularly imports from markets with inconsistent hallmarking standards.
What Those Three-Digit Stamps Mean
Many sellers arrive at AGR Gold's office at 31 West 47th Street with pieces stamped 585, 750, or 417, but with no karat designation. These are fineness marks, used as the standard in Europe, the UK, and most of Asia. They express gold purity in parts per thousand rather than parts per 24.
417 equals 10K. 585 equals 14K. 750 equals 18K. 999 is 24K fine gold. A 750 stamp is not a serial number or a manufacturer's code. It is the precise gold purity measurement, and a trained evaluator uses it to calculate the gold content of a piece. If you have inherited pieces or jewelry purchased abroad, expect fineness marks rather than karat designations.
How Karat Translates Into What a Dealer Pays You
A gold buyer's offer is not calculated by the total weight of the piece. It is calculated from the spot price of pure gold and applied to the actual gold content of your piece. A 10-gram piece of 14K gold contains 5.83 grams of pure gold. The remaining 4.17 grams is alloy with little to no resale value.
For example, if the spot price is at $3,000 per troy ounce (about $96.45 per gram of pure gold), a 10-gram 14K gold item contains roughly $562 worth of pure gold. In comparison, a 10-gram piece of 18K gold at the same price contains about $723 in pure gold. That $161 difference is significant and grows quickly with heavier items or larger collections. Two chains of identical weight and identical visual appearance can receive very different offers on the same day at the same counter, strictly because their karat marks differ.
What the Evaluation Looks Like at AGR Gold
Every evaluation at AGR Gold's Manhattan office happens in front of you. Arnold, Motty, Alex, and Gary work the counter directly. Each piece is weighed separately on a calibrated scale and tested for purity rather than accepted on the basis of the stamp alone.
AGR uses both acid testing and XRF analysis. XRF (X-ray fluorescence) reads metal composition without scratching or damaging the piece, which matters for items with potential collectible value beyond metal content. Acid testing confirms karat through a controlled chemical reaction, the method that has been standard on 47th Street for decades. You see the purity reading, the weight, and the current spot price before any offer is made, and no commitment is required to walk in. With over 40 years of Diamond District transactions behind it, AGR has evaluated pieces from estate lots across all five boroughs, tested unusual fineness marks from international sources, and handled everything from single rings to full collections.
What Sellers Most Often Get Wrong About Gold Purity
The most common mistake sellers make before arriving is weighing gold at home on a kitchen scale and using that number to calculate an expected payout. Kitchen scales are not calibrated to jewelry-grade precision, and they measure in grams rather than troy ounces. One troy ounce is 31.1 grams. A standard ounce is 28.35 grams. Using the wrong unit against a spot price quoted in troy ounces produces an expected figure that is almost always off.
Sellers also assume that heavier automatically means more valuable. Weight matters, but only after purity is confirmed. A 50-gram piece of 10K gold contains less pure gold than a 30-gram piece of 18K gold. The math runs against intuition, which is why karat is confirmed before weight becomes the relevant number.
Damaged gold is consistently underestimated. A broken clasp, a snapped chain, or a single earring without its pair does not affect the gold purity percentage or the metal content. AGR evaluates broken and damaged pieces at the same purity rate as intact jewelry, because the gold in a bent ring is identical to the gold in a perfect one.
Frequently Asked Questions
Does age affect gold purity?
No. Gold does not oxidize or degrade over time. A 14K piece from 1940 carries the same 58.3% gold content as one made this year. Age matters only if a piece has antique or collectible value beyond its metal content.
How do gold dealers test karat?
The two standard methods are acid testing and XRF analysis. Acid testing scratches a small amount of metal onto a stone and applies acid to confirm the karat. XRF reads metal composition without any physical contact. A dealer relying solely on the stamp without independent testing is not providing a fully verified evaluation.
Does a higher karat mean a higher payout when selling?
Per gram of total weight, yes. More pure gold content per gram means a higher payout at the same spot price. The difference compounds significantly on heavier pieces or large lots.
Does damaged gold still have value?
Yes. Physical condition does not affect gold purity percentage or metal content by weight. A broken 18K bracelet is still 75% pure gold and is evaluated at the same rate as an intact piece of the same karat.
What if my piece has no stamp?
AGR tests unstamped pieces to determine whether gold is present and at what purity level. Worn stamps, unusual hallmarks, or repaired pieces can obscure original markings. Testing resolves the question accurately regardless of what the stamp shows.
Who This Applies To
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Sellers with inherited jewelry lots containing mixed karat marks or European fineness stamps
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Anyone who received a quote from a gold buyer and wants to understand what drove the number
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Estate executors in New York City managing collections with pieces from multiple countries or decades.
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Sellers holding damaged or broken gold pieces unsure whether they are worth bringing in
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Anyone with pieces stamped 585, 750, or 417 and no clear karat designation.
Final Takeaway
The karat stamp on a gold piece is a precise measurement of gold purity percentage, and that percentage determines how much of the total weight a dealer is paying for. Understanding what 10K, 14K, 18K, and 24K mean before you walk into a gold buyer's office in Manhattan gives you the language to follow what happens at the counter and the grounding to evaluate whether an offer makes sense.
If you have gold jewelry, inherited pieces, or items with stamps you do not recognize, AGR Gold's Manhattan office at 31 West 47th Street handles walk-in evaluations with no appointment required. Arnold, Motty, Alex, and Gary evaluate every piece in front of you, walk through the purity reading and weight, and make an offer before you commit to anything. Monday through Friday, 9 AM to 6 PM. Call 844-440-GOLD or stop in.