Guide · gold
How to Tell if Gold Is Real: A Jeweler’s Guide to Testing
By Carlos Montejano, founder of Gold Shield
Short answer: To tell if gold is real, first look for a karat hallmark (like 14k or 585) on the piece. Then, perform a magnet test; real gold is not magnetic. Also, check for any skin discoloration or fading on the jewelry itself, which signals it's likely gold-plated.
What's the First Thing to Look for on Gold Jewelry?
The first thing to check is the hallmark, a small stamp indicating the gold's purity, or karat. In my workshop, this is the initial step for any assessment. Look for marks like 10k, 14k, 18k, or their European fineness equivalents—417, 585, and 750—which represent the percentage of pure gold. These stamps are usually found on the clasp of a necklace, the inner band of a ring, or the post of an earring. While a hallmark is a strong indicator of authenticity, its absence doesn't automatically mean the piece is fake, as stamps can wear off over time or may not have been required when the piece was made.
How Can I Tell if Gold Is Real at Home?
The simplest and safest at-home method is the magnet test; since gold is not a magnetic metal, your jewelry should not react to a strong magnet. You can also perform a close visual inspection. Look for discoloration or chipping, especially on edges and high-friction areas. If you see a different colored metal underneath, the piece is gold-plated, not solid gold. Some suggest a ceramic scratch test, but I advise against it as it will damage your jewelry. If the piece is important to you, a non-destructive test is always best.
What's the Difference Between Solid Gold, Gold Plated, and Gold Filled?
Solid gold jewelry is made of a gold alloy through and through, meaning its core is the same as its surface. Gold-plated pieces have a very thin layer of gold (often less than 0.5 microns) electrochemically bonded to a base metal like brass or copper. Gold-filled jewelry has a much thicker layer of gold—at least 5% of the item's total weight—that is mechanically bonded with heat and pressure to the base metal, making it more durable than plating. A high-quality subset of plating is Gold Vermeil, which legally requires a thick layer of gold over a sterling silver base, a standard we use for specific pieces in our gold vermeil collection for its balance of quality and accessibility.
Are There Professional Ways to Verify Gold?
Yes, the most reliable professional methods are X-Ray Fluorescence (XRF) analysis and traditional acid testing. In my Gold Shield workshop, we rely on an XRF scanner, which is a non-destructive device that bombards the metal with x-rays to provide a precise elemental composition without causing any damage. The traditional method, used by jewelers for centuries, involves scratching the piece on a test stone and applying specific concentrations of nitric acid. The acid's reaction (or lack thereof) reveals the karat. However, this method is destructive and can damage the item if not done carefully on an inconspicuous spot.
Do All Real Gold Pieces Have a Hallmark?
No, not all real gold is hallmarked, though standards from organizations like the Federal Trade Commission (FTC) in the U.S. require it for commercially sold items to be marketed as gold. Very old, antique jewelry may predate hallmarking laws. Custom-made pieces might also lack a stamp if the creator didn't apply one. Furthermore, hallmarks on well-loved, frequently worn items can simply wear away over many years. So, while a hallmark is a great sign of authenticity, its absence requires further testing to make a final determination.
What Do Different Gold Purity Levels Mean?
Gold purity, measured in karats (k), defines the ratio of pure gold to the other metal alloys mixed in for strength and color. Pure gold is 24k (99.9% gold), but it's too soft for most jewelry. Therefore, it's alloyed with metals like copper, silver, and zinc. 18k gold is 75% pure gold, 14k is 58.5%, and 10k is 41.7%. The lower the karat, the more durable the piece, but the less pure gold it contains. The choice of karat is a balance between value, color, and the durability needed for the piece's intended use.
| Material/Karat | Pure Gold Content | Fineness Stamp | Common Alloys | Mohs Hardness (approx.) |
|---|---|---|---|---|
| 24k Gold | 99.9% | 999 | None | 2.5 |
| 18k Gold | 75% | 750 | Copper, Silver, Nickel | 2.75 |
| 14k Gold | 58.5% | 585 | Copper, Silver, Nickel, Zinc | 3.0 |
| 10k Gold | 41.7% | 417 | Copper, Silver, Nickel, Zinc | 3.5-4.0 |
| Sterling Silver | 92.5% (Silver) | .925 | Copper | 2.5-3.0 |
Free guide
Is your gold real? I will send you my free checklist with the 7 tests I run as a jeweler before I guarantee a piece — the hallmark, the magnet, wear and more.
Frequently Asked Questions
What is the price per gram of 10k, 14k, and 18k gold in Mexico today?
The price of gold changes daily based on international markets. As of early 2026, you might see approximate raw gold values around $1,100 MXN for 10k, $1,550 MXN for 14k, and $2,000 MXN for 18k per gram. However, you must always check the current day's spot price. The retail price of jewelry will be higher to account for design, labor, and craftsmanship.
What is the difference between 10k, 14k, and 18k gold?
The difference is the percentage of pure gold. 18k gold contains 75% pure gold, making it more valuable and giving it a richer yellow hue. 14k gold contains 58.5% pure gold and offers a great balance of color, value, and durability. 10k gold contains 41.7% pure gold, making it the most durable and affordable of the three, though with a paler color.
Which gold karat is best for everyday wear?
For everyday wear, 14k gold is often the best choice. It provides an excellent combination of durability to resist scratches and dents from daily life, a beautiful gold color, and a more accessible price point than 18k. While 10k is even more durable, some find its color less rich. 18k is beautiful but softer and more prone to scratching.
How do I know if a piece of jewelry is real gold?
To know if gold is real, look for a hallmark stamp (e.g., 14k, 585), test it with a magnet (real gold isn't magnetic), and check for any green or black discoloration on your skin or worn-off color on the piece itself. For 100% certainty, have it tested by a professional jeweler with an XRF scanner or acid test.
Are there more affordable alternatives to gold and diamonds for jewelry?
Absolutely. For a gold look, high-quality gold vermeil (a thick gold layer over sterling silver) is an excellent alternative. Sterling silver itself is a beautiful and classic precious metal. For diamonds, moissanite is a popular alternative; it's nearly as hard (9.25 on the Mohs scale vs. diamond's 10) and has even more fire and brilliance. White sapphires and high-quality cubic zirconia are other options.
Where can I buy gold with confidence in Mexico City?
To buy gold with confidence in CDMX or anywhere, look for established jewelers with a physical presence and a history of positive reviews. A trustworthy seller will be transparent about materials, provide authenticity certificates (like those from the Gemological Institute of America, or GIA), and explain their pricing. Avoid high-pressure sales and seek out workshops that are proud of their craft, as we strive to be at Gold Shield.
What is Florentine gold?
Florentine gold refers to a surface finishing technique, not a type of gold. It creates a textured, cross-hatched pattern of fine, brushed lines on the metal's surface. This finish reduces reflectivity and gives the piece a unique, matte-like luster. It's achieved by engraving parallel lines with a special tool and then turning the piece to engrave another set of lines perpendicular to the first.
How much does a 14k Florentine gold piece cost?
The cost of a 14k Florentine gold piece depends primarily on its weight, the complexity of the design, and the labor involved. The Florentine finish itself adds to the labor cost. You would calculate the base value from the gold weight and then add a significant premium for the artisan's skill and time to create the intricate finish.
What do gold hallmarks mean?
Gold hallmarks are stamps that certify the metal's purity. A karat mark (10k, 14k, etc.) tells you the gold content. A fineness mark (417, 585, 750) is the European equivalent, representing parts per thousand of pure gold. You might also see a maker's mark, which identifies the workshop or designer who created the piece.
Does high-quality gold wear down or change color?
High-quality solid gold does not tarnish or change color. However, it is a relatively soft metal, so it can wear down, scratch, and dent over decades of constant use. The alloys mixed with the gold can sometimes react to chemicals or skin pH, but this is rare in 14k or 18k gold. If your "gold" jewelry is changing color or leaving marks, it's almost certainly gold-plated.
How do I calculate the value of a 14k gold piece based on its weight?
First, find the current spot price of pure gold per gram. Then, use this formula: (Current Gold Spot Price per gram) x 0.585 (for 14k) x (Weight of your item in grams). This gives you the raw melt value of the gold. The actual market value of the jewelry will be higher, as it includes craftsmanship, design, and retail markup.