The stamp is your fastest identifier. Plain karat marks (10K, 14K, 18K) mean solid gold. “GF” or a fraction like “1/20 12K GF” means gold filled. “GP,” “GEP,” “HGE,” or “RGP” mean gold plated or electroplated. Solid gold is worth its full weight in metal. Gold filled yields value only in bulk lots. Gold plated items are worth their base metal, and the gold layer is too thin to recover profitably at household scale.
If you are sorting through a jewelry box, an estate collection, or a drawer of older pieces, you are facing one of the most misunderstood distinctions in secondhand gold. The differences in value are dramatic. A 14K gold ring weighing five grams has meaningful melt value. An identical-looking ring stamped “GF” is worth a fraction of that. A ring stamped “HGE” has negligible recoverable gold. This guide explains how to tell each apart and what realistic value to expect from each category.
Reading the Stamps: A Quick Reference Table
The most reliable starting point for any piece of jewelry is the hallmark stamp. Stamps are small and sometimes faded, but they carry legally specific meanings in the United States under the Federal Trade Commission’s Jewelry Guides, codified at 16 CFR Part 23.
Here is how to read what you find. Examine clasps, ring shanks, and back surfaces with a magnifying glass or loupe under good light.
| Stamp Found | What It Means | Category |
|---|---|---|
| 10K, 10KT, 417 | 41.7% pure gold, solid throughout | Solid gold |
| 14K, 14KT, 585 | 58.3% pure gold, solid throughout | Solid gold |
| 18K, 18KT, 750 | 75% pure gold, solid throughout | Solid gold |
| 22K, 22KT, 916 | 91.7% pure gold, solid throughout | Solid gold |
| 24K, 24KT, 999 | 99.9% pure gold; too soft for everyday wear jewelry | Solid gold |
| GF, 1/20 12K GF, 1/10 14K GF | Gold filled: solid gold layer bonded to base metal, minimum 1/20 of total weight | Gold filled |
| GP, G.P. | Gold plated: electroplated layer over base metal | Gold plated |
| GEP | Gold electroplated | Gold plated |
| HGE, H.G.E. | Heavy gold electroplate: minimum 2.5 microns of at least 10K gold per FTC rules | Gold plated |
| RGP | Rolled gold plate: mechanically bonded thin layer, thinner than gold filled | Rolled gold plate |
| 925 (with gold color) | Sterling silver base: may be gold vermeil if accompanied by a gold content mark | Gold vermeil or silver |
A few practical notes: European pieces use numeric hallmarks (585 = 14K, 750 = 18K, 999 = 24K). Older American pieces from the early 20th century sometimes carried just “GF” without the fraction. If you see a fraction like “1/20,” the numerator is the minimum proportion of the item’s total weight that is gold-layer material.
Solid Gold: Karat Marks and Full Melt Value
Solid gold is the only category where the entire metal alloy contains gold throughout. “Solid” does not mean pure: in jewelry, gold is always alloyed with other metals (copper, silver, zinc) to improve durability. What it means is that there is no base metal core. Every gram of a solid gold piece contributes to its melt value.
Karat marks and purity percentages
The karat system divides purity into 24 parts. A piece stamped 14K contains 14 parts gold and 10 parts other metals, equaling 58.3% gold by weight. The FTC requires that any jewelry sold or described as “gold” in the United States be at least 10 karat. Pieces below that threshold cannot legally carry a karat mark.
| Karat | Gold Purity | US Stamp | European Mark | Common Use |
|---|---|---|---|---|
| 10K | 41.7% | 10KT | 417 | Fashion jewelry, class rings |
| 14K | 58.3% | 14KT | 585 | Most US fine jewelry |
| 18K | 75.0% | 18KT | 750 | Higher-end pieces, European jewelry |
| 22K | 91.7% | 22KT | 916 | Gold coins, South Asian jewelry |
| 24K | 99.9% | 24KT | 999 | Bullion bars and coins |
For a detailed look at how the karat system works across different product types, see our guide on understanding gold karats.
How to estimate melt value
To estimate what a solid gold piece is worth in metal alone, you need its weight in grams, its karat purity, and the current spot price of gold per troy ounce. One troy ounce equals 31.1 grams. The formula: multiply the weight in grams by the gold purity percentage, then divide by 31.1, then multiply by the spot price per troy ounce.
For a practical walkthrough with current prices, use our gold value calculator. Keep in mind that dealers and refiners typically pay between 70 and 95 percent of melt value, depending on volume, buyer relationship, and piece condition.
Gold Filled: FTC Rules, Stamps, and What It Is Worth
Gold filled is a step below solid gold but a meaningful step above gold plated. The FTC’s Jewelry Guides define it precisely at 16 CFR § 23.4: the gold content of a gold-filled item must constitute at least 1/20 of the total metal weight of the item, and the gold used must be at least 10 karat.
Reading the gold filled stamp
The stamp tells you both the proportion and the karat of the gold layer:
- 1/20 12K GF: the gold layer is 12K gold (50% pure) and constitutes at least 1/20 (5%) of the total item weight. Actual gold content by total weight: 2.5%.
- 1/20 14K GF: the gold layer is 14K gold (58.3% pure) and constitutes at least 1/20 of the total weight. Actual gold content: 2.9%.
- 1/10 14K GF: the gold layer is 14K gold and constitutes at least 1/10 (10%) of the total weight. Actual gold content: 5.8%.
- GF alone: older pieces may carry just “GF.” By default this still implies at least 1/20 of at least 10K gold, though the exact specification may require a jeweler to confirm.
The chart below shows how dramatically different the gold content percentage is across jewelry types, based on FTC minimum standards.
What gold filled is actually worth
Gold filled items do contain real gold, and refiners do process gold filled scrap. The challenge is volume. A single gold filled necklace might yield a fraction of a gram of actual gold content after refining. Most retail refiners charge minimum processing fees that make individual pieces economically unworkable.
Gold filled scrap becomes worth processing when you accumulate enough to reach a refiner’s minimum lot requirement. Industry buyers who specialize in this category (estate lot buyers, specialized scrap refiners) pay a per-pound rate for gold filled material rather than pricing individual pieces. If you have a substantial estate collection consisting primarily of gold filled jewelry, contacting a specialized refiner directly is the appropriate path.
The most common identification mistake
The most frequent disappointment we see from estate sellers: a piece stamped “14K GF” or “1/20 14K GF” is assumed to be solid 14K gold. The “14K” in a GF stamp refers only to the karat of the gold layer itself, not the piece as a whole. The presence of “GF” anywhere in a marking means gold filled, without exception. There is no industry use of “GF” as an abbreviation for anything else in jewelry context.
Gold Plated and Electroplated: Stamps Decoded
Gold plated items are base metal (usually brass, copper, or steel) with an extremely thin gold layer applied through electroplating. The gold layer is measured in microns. In most consumer jewelry, it ranges from 0.5 to 2.5 microns thick.
The different plating stamps and what they mean
The FTC distinguishes between plating categories based on minimum thickness requirements, but all of them share one economic reality: the gold layer is too thin to recover profitably in household quantities.
| Stamp | Full Name | FTC Minimum Thickness | Recoverable Gold Value |
|---|---|---|---|
| GP / GEP | Gold plated / Gold electroplated | No minimum specified | Negligible; cents at household scale |
| HGE | Heavy gold electroplate | 100 millionths of an inch (approx. 2.5 microns) of at least 10K gold | Negligible; cents at household scale |
| RGP | Rolled gold plate | Below the 1/20 gold-filled threshold; mechanically bonded | Base metal value only |
Rolled gold plate (RGP) is sometimes confused with gold filled because the gold layer is mechanically bonded rather than electroplated. The key difference is proportion: rolled gold plate has a thinner gold layer relative to total weight than gold filled, placing it below the FTC’s 1/20 minimum threshold for the gold filled designation.
Why household quantities do not justify refining
A standard gold plated ring with 1 micron of gold covering roughly 10 square centimeters of surface area contains approximately 0.02 grams of gold. At any realistic spot price, that translates to cents of recoverable metal, far below any refiner’s minimum processing fee. Even at the HGE maximum of 2.5 microns, the recoverable value remains in the same range: cents, not dollars.
The practical value of gold plated jewelry lies in its wearable condition for resale at vintage or thrift markets, its craftsmanship, or any collectible merit the design may carry. Not its metal content.
Beyond the Stamp: Physical Tests for Unmarked Pieces
Many older pieces are unmarked, or stamps have worn away over decades of use. When the stamp is absent or illegible, several physical tests help narrow down the category before spending money on professional assessment.
Magnet test
Gold is not magnetic. Neither are copper, brass, or silver, which are the most common base metals in fine and semi-fine jewelry. Iron and nickel are strongly magnetic. If a piece is firmly attracted to a rare-earth (neodymium) magnet, the base is iron or contains significant nickel. That is a quick disqualifier for solid gold or high-quality gold filled: pieces that stick to a magnet are almost certainly plated over a ferrous or nickel-heavy base, common in inexpensive costume pieces from mass-market retailers. A weak attraction may suggest stainless steel with surface plating.
Wear point inspection
Examine the areas of highest friction under a magnifying glass: clasp backs, the underside of ring shanks, necklace link contact points, and any raised design edges. On plated pieces, the gold layer wears through at these points first, revealing the base metal color (yellow-orange copper, reddish brass, or silver-toned steel). On gold filled pieces, wear may eventually reveal the base layer, but it takes significantly longer because the gold layer is mechanically bonded and substantially thicker. Solid gold shows consistent color at all wear points, even at heavily used areas.
Acid test
Acid testing is the traditional method used by jewelers and scrap buyers. A small scratch is made in an inconspicuous location (inside a ring shank, the back of a pendant), and a drop of nitric acid is applied. Solid gold at 10K or higher shows no reaction to dilute nitric acid. Lower karat alloys or base metals react with color changes: green indicates copper, milky white indicates silver, and various other colors indicate other alloys. Gold test kits with nitric acid at different dilutions are sold by jewelry supply retailers and allow rough karat identification without professional equipment.
Note that acid testing is slightly destructive. For pieces with potential collector or artistic value, consult a professional appraiser before testing.
XRF (X-ray fluorescence) testing
XRF testing is the professional standard for non-destructive metal identification. A handheld XRF device reads the fluorescence spectrum when the metal is exposed to X-rays and identifies the exact elemental composition, including gold percentage, base metals present, and plating layer thickness. Many coin dealers, pawn shops, and precious metals buyers maintain XRF devices on-site. If you have a large or potentially valuable collection, asking any prospective buyer to XRF-test the pieces before you accept an offer gives you objective data for comparison and negotiation.
For a comprehensive guide to reading jewelry hallmarks, including antique and European marks, see our jewelry hallmarks identification guide. For gold vermeil specifically (sterling silver base with a gold layer), see our guide on gold vermeil explained.
What Each Type Is Worth: The Honest Picture
Below is a realistic summary of recoverable value for each category. These are guidelines based on typical market conditions. The actual offer you receive depends on the specific buyer, current spot price, lot size, and piece condition.
| Type | Gold Content (by weight) | Practical Recoverable Value | Best Buyer Type |
|---|---|---|---|
| Solid 10K gold | 41.7% | 70-95% of melt value; use spot price calculator | Jeweler, scrap buyer, refiner |
| Solid 14K gold | 58.3% | 70-95% of melt value; use spot price calculator | Jeweler, scrap buyer, refiner |
| Solid 18K gold | 75.0% | 70-95% of melt value; use spot price calculator | Jeweler, scrap buyer, refiner |
| Gold filled (1/20 12K GF) | 2.5% | Modest per-pound rate in bulk; cents per individual piece | Specialized estate/dental refiners |
| Gold filled (1/10 14K GF) | 5.8% | Modest per-pound rate in bulk; cents per individual piece | Specialized estate/dental refiners |
| Gold plated (GP, GEP) | Under 0.05% | Effectively zero for household quantities | Vintage/costume resale market |
| Heavy gold electroplate (HGE) | Under 0.05% | Effectively zero for household quantities | Vintage/costume resale market |
| Rolled gold plate (RGP) | Below GF threshold | Effectively zero for household quantities | Vintage/costume resale market |
Quick sorting guide for a mixed jewelry box
Start with stamps. Use a magnifying glass and examine clasps, ring shanks, and back surfaces in good light. Sort into three piles: karat-stamped pieces (solid gold candidates), GF/RGP-stamped pieces (gold filled or rolled gold), and everything else (plated, costume, or unmarked). Then run a magnet pass on the unmarked pile: anything that sticks firmly to a rare-earth magnet is almost certainly plated over iron or nickel-heavy steel. What remains unmarked and non-magnetic could be solid gold, silver, or base metal without a stamp. Have those pieces tested by a jeweler before selling.
Selling a Mixed Collection: Get Competing Offers
If you have estate jewelry and want to know what buyers will actually pay for your specific pieces, the most effective approach is collecting multiple offers before committing to any buyer. Post one free request on Goldiew’s sell-gold page and receive sealed offers from up to 15 verified buyers, with no obligation. You can also browse active listings on the Goldiew Marketplace to see what comparable pieces are currently trading for.
Frequently Asked Questions
Is gold filled worth anything if I want to sell it?
Gold filled contains real gold, but a single piece yields very little recoverable metal. Individual pieces are not economically practical to refine once processing fees are factored in. If you have a substantial lot, such as several pounds of gold filled scrap from an estate, specialized refiners who handle estate jewelry and dental scrap will pay a per-pound rate. For smaller quantities, resale as wearable jewelry or vintage items is usually the better path, where craftsmanship and condition drive value more than metal content.
How can I tell if a piece is gold filled or solid gold without visiting a jeweler?
Check the stamp first with a loupe or magnifying glass. A plain karat mark (10K, 14K, 18K, 585, 750) with no “GF” anywhere in the marking means solid gold. Any stamp containing “GF,” a fraction like “1/20,” or “RGP” means gold filled or rolled gold plate, not solid. If the piece is unmarked, a rare-earth magnet test and a visual inspection of wear points (clasps, edges, underside of ring shanks) under magnification provide useful preliminary data. For certainty on unmarked pieces, an acid test kit or XRF reading from a local buyer will confirm the category without requiring a formal appraisal.
What does “1/20 12K GF” mean exactly?
The stamp has three components. “1/20” means the gold layer constitutes at least one-twentieth (5%) of the total metal weight of the piece. “12K” means the gold used in that layer is 12 karat, which is 50% pure gold. “GF” stands for gold filled. The actual gold content as a percentage of total weight is therefore 1/20 multiplied by 50%, which equals 2.5%. The Federal Trade Commission’s Jewelry Guides at 16 CFR § 23.4 define the minimum standards for using this designation.
Can gold plated jewelry be recycled for its gold?
Technically yes, but economically no at household scale. Commercial electronic recyclers process large volumes of gold-plated circuit boards and industrial connectors where accumulated gold adds up to meaningful weight. A personal collection of gold plated jewelry contains far too little gold to cover refining costs. The practical value for a household seller is resale as wearable or vintage items, not metal recovery.
Does “HGE” mean the piece is close in value to gold filled?
No. “Heavy” in HGE refers to the maximum thickness category within electroplating, not to thickness that approaches gold filled levels. The FTC requires HGE to have at least 100 millionths of an inch (approximately 2.5 microns) of at least 10K gold. Gold filled requires the gold layer to constitute at least 1/20 of the total weight of the item, which represents a far greater amount of gold. The gold content in HGE is a small fraction of what gold filled contains, and both are dramatically lower than solid gold.
Are antique gold filled pieces worth more than their metal?
Potentially, yes. Antique and vintage gold filled jewelry from the early to mid-20th century, particularly Victorian, Art Nouveau, Art Deco, and mid-century Modernist pieces, can carry significant collector and resale value based on design, maker’s marks, and condition, independent of metal content. If you find ornate or signed pieces in good condition, research the maker before approaching a scrap buyer. A vintage or antique jewelry specialist may return substantially more than any metal-based price.
What is the difference between gold filled and gold vermeil?
Gold vermeil is a specific type of gold plating over a sterling silver (.925) base. The FTC requires gold vermeil to have a sterling silver base, a minimum of 2.5 microns of gold, and the gold must be at least 10 karat. Gold filled, by contrast, uses a brass or copper base but has a substantially thicker total gold layer as a proportion of the item’s total weight. Vermeil’s value exceeds standard gold plate because the sterling silver base retains its own scrap value. For a detailed breakdown, see our guide on gold vermeil explained.
Can I identify gold filled jewelry by how it looks or feels?
Visual and tactile inspection alone cannot reliably distinguish gold filled from solid gold. Both can have identical color, weight, and finish. Gold filled pieces wear longer than plated items (the layer is much thicker), which can make them look convincingly solid for years. The stamp is the only reliable non-destructive indicator at home. If a piece has no readable stamp, physical tests (magnet, wear point, acid, XRF) are needed to determine the category.
Sources
- Federal Trade Commission, 16 CFR Part 23, “Guides for the Jewelry, Precious Metals, and Pewter Industries” (eCFR): definitions for gold filled (§ 23.4), gold plated (§ 23.6), electroplated (§ 23.5), karat standards, and heavy gold electroplate thickness requirements
- Federal Trade Commission, Jewelry Guides overview: regulatory basis and enforcement context for US gold marking requirements
- FTC Consumer Information: Shopping for Jewelry: consumer guidance on interpreting gold purity markings and avoiding misrepresentation