18k, 14k, and 9k Gold: differences, value, and how to identify 750
Posted by REDAZIONE GIOIELLI TOSTI
In short: In Italy, 18k gold is stamped 750: it contains 75% pure gold (750 parts per 1000), compared to 58.5% for 14k (585) and 37.5% for 9k (375). The higher the purity, the more intense the color and the greater the resistance to oxidation. To identify it, look for the 750 hallmark and the manufacturer's mark engraved on the jewelry.
The Carat and Millesimal Fineness System: How it Works
When talking about gold for jewelry, two parallel systems are used: carats (24k = pure gold) and millesimal fineness (number of gold parts per 1000). In Italy and Europe, the legal system is millesimal fineness, and every piece of jewelry must bear a hallmark with its fineness before being sold.
Complete Table: Carats, Millesimal Fineness, and Color
| Caratage | Millesimal Fineness | % Pure Gold | Italian Hallmark | Typical Color | Common Use |
|---|---|---|---|---|---|
| 24k | 999 | 99.9% | 999 | Intense Yellow | Ingots, Investment |
| 18k | 750 | 75% | 750 | Warm Yellow / White / Rose | Quality Made in Italy Jewelry |
| 14k | 585 | 58.5% | 585 | Lighter Yellow | USA Market, Mid-Range Jewelry |
| 9k | 375 | 37.5% | 375 | Pale Yellow | Precious Costume Jewelry, UK |
Why Italy Uses Millesimal Fineness (750, 585, 375) Instead of Carats
The millesimal fineness system is more precise and better suited for legal control. In Italy, the law requires every goldsmith to hallmark their jewelry with the millesimal fineness and an identifying manufacturer's mark, registered with the Chamber of Commerce. The system is harmonized at a European level by the precious metals directive.
"The Italian millesimal fineness system (750 = 18k) is regulated by law: every piece of jewelry must bear the fineness hallmark and the manufacturer's mark before being sold." — Italpreziosi
18k Gold (750): Why it's the Italian Standard for Quality Jewelry
18k gold is the perfect balance between purity and durability. With 75% pure gold, it is noble enough not to tarnish skin or oxidize, and robust enough – thanks to the 25% alloy – to withstand daily wear without deforming.
Alloy Composition: Copper, Silver, Palladium
The remaining 25% of the alloy varies depending on the color:
- 18k Yellow Gold: copper and silver in classic proportions that maintain a warm tone
- 18k White Gold: palladium (sometimes nickel in cheaper alloys) + rhodium finish that gives a brilliant white
- 18k Rose Gold: a higher proportion of copper, which gives it a bronzed/rosy tone
Why 750 Gold Does Not Tarnish Skin
Skin discoloration is caused by low-carat alloy metals (especially copper in high percentages). With 18k gold, the amount of alloy is contained and well-balanced: under normal daily use, it does not leave dark halos or stains. Sweat and perfumes can dull the surface over time, but this can be resolved with gentle cleaning.
18k vs 14k vs 9k Comparison: Color, Durability, Value
| Characteristic | 18k Gold (750) | 14k Gold (585) | 9k Gold (375) |
|---|---|---|---|
| % Pure Gold | 75% | 58.5% | 37.5% |
| Color | Warm and Intense Yellow | Slightly Lighter Yellow | Pale Yellow |
| Oxidation Resistance | High — does not tarnish | Good | Moderate — may tarnish over time |
| Hardness | Medium — suitable for elaborate jewelry | Slightly harder | Harder but more brittle in the long run |
| Intrinsic Value | High | Medium | Low |
| Prevalence in Italy | Market Standard | Rare — mainly USA imports | Rare — mainly UK market |
14k Gold is Common in the US but Rare in Italian Jewelry: Why
Italian goldsmith tradition has always favored 18k gold for its purity and warmer color. 14k gold became popular in the United States as a more accessible price point, but in Italy, a piece of 14k gold jewelry is still considered non-standard today. If you purchase 585-marked jewelry in Italy, you should still verify its origin.
How to Recognize 18k Gold: The 750 Hallmark
The surest way to verify the fineness of a piece of jewelry is to look at the hallmark: a microscopic engraving (or stamp) that shows the millesimal fineness and the manufacturer's code.
Where to Find the Hallmark
- Rings: inside the shank (the part that touches the finger)
- Necklaces and Bracelets: on the clasp or on the lobster clasp
- Earrings: on the post or clip, often visible with a magnifying glass
- Pendants: on the bail or on the back of the pendant
The Manufacturer's Mark: Who Issues it and What it Guarantees
In addition to the fineness (750), Italian jewelry bears a second hallmark: the manufacturer's mark, composed of a symbol + letters + provincial number, registered with the Chamber of Commerce. This mark uniquely identifies the producer and guarantees that the jewelry was manufactured in compliance with precious metal regulations.
What if There's No Hallmark?
Antique jewelry (pre-1968 in Italy) may not have the modern format hallmark. Jewelry purchased abroad (especially outside the EU) may not comply with the same regulations. In these cases, a trusted jeweler can perform a fire assay or use an acid test kit to determine the fineness with certainty.
Does 18k Gold Change Color or Get Damaged?
Yellow 18k gold, under normal conditions of use, does not change color. Its percentage of pure gold is sufficient to make it stable. It can become dull due to deposits of cream, sweat, or perfume, but it cleans easily with a soft cloth or a brief immersion in lukewarm water with a few drops of neutral soap.
Differences in Durability between 18k, 14k, and 9k in Daily Use
Paradoxically, 9k gold — despite being harder due to the greater amount of alloy metals — is the most prone to oxidation and skin tarnishing in the long run, precisely because the alloy (with more copper) reacts faster to contact with sweat, perfumes, and humidity.
How to Clean and Store 18k Gold Jewelry
- Remove jewelry before showering, swimming in a pool, or using chemicals.
- For routine cleaning: use a microfiber cloth and gentle rubbing.
- For deeper cleaning: immerse for 5 minutes in lukewarm water + neutral soap, then dry with a soft cloth. Avoid stiff brushes on set gemstones.
- Store each piece of jewelry separately to prevent scratches.
How Much is 18k Gold Worth (Quotation and What Affects the Price)
The price of an 18k gold jewel depends on three factors: the quotation of the metal (which varies daily on the London Bullion Market), the weight in pure gold, and the value of the craftsmanship (an artisan Made in Italy jewel is worth much more than just the weight of the metal). There is no "fixed price" for gold: the quotation is public and verifiable in real-time.
An 18k gold Made in Italy necklace has an intrinsic value guaranteed by the metal, plus an artisanal value that preserves over time — unlike plated or gilded gold, where the gold layer is very thin and wears away.
Tosti Jewelry's 18k Gold Jewelry: 750/1000, Made in Italy, Certified
At Gioielleria Tosti in Cosenza, since 1972, we deal exclusively in 750/1000 (18k) gold jewelry of certified Italian production. Each piece bears the 750 hallmark and the manufacturer's mark. You can verify this in person at our store or contact us on WhatsApp for any clarification before purchasing.
Discover 18k gold necklaces for women →
18k gold rings for women →
18k gold bracelets for women →
18k gold necklaces for men →
Do you have questions about the jewelry you own or want to buy? Write to us on WhatsApp — the owner will reply.
Frequently Asked Questions about 18k Gold
What does 750 mean on gold?
The number 750 is the millesimal fineness hallmark that indicates the purity of gold: 750 parts of pure gold out of 1000, which is 75%. This corresponds to 18-carat gold and is the legal Italian standard for quality jewelry. Every piece of jewelry sold in Italy must bear this hallmark along with the manufacturer's mark.
Is 18k gold better than 14k?
In Italy, yes, and for almost all uses. 18k gold contains 75% pure gold compared to 58.5% for 14k: it has a warmer and more intense color, does not tarnish skin, maintains its appearance better over time, and has a higher intrinsic value. 14k can be slightly harder, but this advantage does not justify the lower purity for quality jewelry.
Does 18k gold tarnish?
No, under normal conditions of use, 18k gold does not tarnish skin or oxidize. It can become dull due to deposits of cream or sweat, but it cleans easily. It is low-carat gold (especially 9k) that can leave dark marks, because it contains a higher percentage of copper that reacts to chemical agents.
How do you read the hallmark on gold?
The hallmark is engraved on the least visible part of the jewelry: inside the ring, on the clasp of a necklace or bracelet. You can read it with a magnifying glass. You will find the fineness number (750 for 18k gold) and next to it the manufacturer's identifying mark (letters + provincial number).
Is 18k gold hypoallergenic?
It depends on the alloy. Yellow and rose 18k gold does not contain nickel (the main allergens are nickel and cobalt, used in some cheaper alloys). White 18k gold traditionally contained nickel, but today most quality Italian jewelry uses palladium instead, which is much less allergenic. For sensitive skin, choose 18k white gold with a palladium alloy or ask your jeweler for confirmation.
Article written by the editorial staff of Gioielleria Tosti — Cosenza, since 1972. Official distributor of certified Italian jewelry.
Published on 2026-06-23 | Updated on 2026-06-23
SHARE: