How Gold Is Tested

A transparent look at the testing process behind every gold offer we make.

Trusted Since 2014A decade serving San Diego
Licensed & InsuredCalifornia-licensed pawnbroker
Thousands of TransactionsDiamonds, watches, gold & more
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How Gold Testing Works: Quick Answer

Gold is valued on purity and weight. Here is how we determine both, without damaging your item:

  • Karat marks indicate purity — 24k is 99.9% pure, 18k is 75%, 14k is 58.5%, and 10k is 41.7%, the U.S. legal minimum to be sold as gold.
  • International pieces use fineness numbers instead: 999, 916, 750, 585, and 417 correspond to the same purities.
  • We verify rather than trust the stamp. Acid testing, electronic conductivity testing, and XRF analysis confirm actual purity.
  • XRF testing is completely non-destructive and reads the elemental composition of the metal without marking the piece.
  • Gold-plated and gold-filled items are not solid gold and carry substantially less value, our testing distinguishes them clearly.
  • Weight is measured on a certified scale in front of you, and the offer is calculated from purity plus weight against the current spot price.

Understanding Karat Markings

Gold purity is measured in karats, out of a possible 24: 24k is 99.9% pure gold, 18k is 75% gold, 14k is about 58.3%, and 10k is about 41.7%, the minimum legally sold as “gold” in the U.S.

Gold jewelry being evaluated for purity at DCL Jewelry & Loan

How We Test Your Gold

Visual inspection starts with any karat stamps or hallmarks, which we then verify with testing. Acid testing uses solutions calibrated to specific karat levels on a small, unnoticeable area. Electronic and XRF testing measures metal composition without damaging the item at all for higher-value pieces. Once purity is confirmed, we weigh your item precisely and calculate your offer from the actual pure gold content at the current market price.

Gold buyer testing jewelry purity in San Diego

What About Gold-Plated or Gold-Filled Items?

These items contain only a thin layer of gold over a base metal and generally have minimal scrap value compared to solid gold. We’re happy to evaluate them, but expect a much lower offer than for solid gold pieces of similar size.

Ready to sell? See our Sell Gold page.

International Gold Purity (Fineness) Chart

KaratFineness HallmarkPure Gold Content
24k99999.9% (pure gold)
22k91691.6%
18k75075.0%
14k58558.5%
10k41741.7% (U.S. legal minimum for “gold”)

Many pieces, especially those made outside the U.S., are stamped with the fineness number (750, 585, etc.) instead of, or in addition to, the karat number.

Additional Testing Methods

Beyond acid, electronic, and XRF testing, a few other methods are used in the industry:

  • Specific gravity testing — measures density by comparing an item’s weight in air versus water, since gold has a distinctive density that alloys and fakes typically don’t match.
  • Magnet testing — a quick screening step; genuine gold is not magnetic, so an item that’s strongly attracted to a magnet is not solid gold (though this alone doesn’t confirm purity).
  • Fire assay — the most precise method, used primarily by refiners, it involves melting a sample and separating the gold, this is generally not needed for routine evaluations.

Spotting Counterfeit or Misrepresented Gold

Common red flags include items stamped with a karat marking that doesn’t match their test results, unusually light weight for their apparent size, or a magnetic response. Gold-plated and gold-filled items are not counterfeit, they’re legitimately manufactured, but they’re sometimes mistakenly represented as solid gold. Our testing process catches all of these cases before we make an offer.

Gold We Test & Buy Every Day

Real pieces and real work from our Carmel Valley showroom — not stock catalogue photography.

Gold jewelry being evaluated at DCL Jewelry & Loan San Diego
Seller recommending gold products to a customer
Gold bullion bars
Gold jewelry with bracelets, rings and necklaces in a luxury shop
Gold buyer weighing jewelry in San Diego
Gold wedding bracelet and fine gold jewelry

Why San Diego Chooses DCL Jewelry & Loan

Non-Destructive XRF Analysis

X-ray fluorescence reads the actual elemental composition of your gold without scratching, cutting, or otherwise marking the piece.

Licensed California Pawnbroker

We operate under California Department of Justice pawnbroker licensing, which means regulated recordkeeping, defined loan terms, and legal protections for you and your property.

Fully Confidential

No credit checks, no employer calls, no reporting to credit bureaus. Private appointments are available for high-value pieces, and your transaction stays between you and us.

Evaluated In Front of You

Your item never leaves the room. We test, inspect, and explain exactly how we reached a number, so you can see the reasoning rather than just the offer.

Secure, Insured Storage

Items held as collateral are stored in a secured, insured environment for the duration of the loan and returned in the same condition.

Same-Day Funding

Most evaluations are completed during your visit, and funding is available the same day once you accept an offer.

Serving San Diego Since 2014

A decade of local transactions across diamonds, luxury watches, gold, and estate jewelry, with a public Google review record you can read before you visit.

Related Services

What San Diego Gold Sellers Say About Us

Gold & Fine Jewelry From Our Collection

Areas We Serve Across San Diego County

Our Carmel Valley showroom serves clients throughout San Diego County, with private appointments available for high-value pieces.

Carmel ValleyDel MarLa JollaRancho Santa FePowayEncinitasSolana BeachCarlsbadCoronadoPoint LomaDowntown San DiegoUTC / University CityScripps RanchRancho Bernardo4S RanchNorth County

More From DCL Jewelry & Loan

See more real evaluations, tips, and behind-the-scenes looks on our YouTube channel.

Frequently Asked Questions

Acid testing is done on a small, unnoticeable area, and modern electronic or XRF testing doesn’t damage the item at all.

We can still test and determine the purity directly, a karat stamp isn’t required for us to evaluate your item.

Gold-plated and gold-filled items have much less scrap value than solid gold since they contain only a thin gold layer, but we’re happy to evaluate them.

We multiply the item’s weight by its confirmed purity percentage to determine pure gold content, then price that against the current market rate for gold.

Yes, evaluations happen in front of you during your appointment.

Yes, gold is priced on a global commodity market that moves throughout each trading day, so your offer reflects current market pricing.

These are fineness hallmarks used internationally: 750 means 75% pure gold (18k), and 585 means 58.5% pure gold (14k).

Genuine gold isn’t magnetic, so a strong magnetic response means the item isn’t solid gold. This is a quick screening test, not a full purity confirmation.

Gold-filled items have a thicker, mechanically bonded layer of gold over a base metal, while gold-plated items have a much thinner electroplated layer. Both have limited scrap value compared to solid gold.

Fire assay is the most precise gold testing method, used primarily by refiners. It’s generally not necessary for routine evaluations, our acid, electronic, and XRF testing provide accurate results for standard purchases.

Yes, it involves weighing the item in air and then in water, with no damage to the piece.

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