If you look closely at a fine jewelry piece, you may notice a small engraving on the metal. It could appear on a necklace chain tag, the back of a pendant, the inside of a ring, or the back of an earring.
One common mark is Au750. It may look technical, but the meaning is simple: the piece is made with 18K gold.
At J'ENCHANTE, our 18K gold jewelry is marked with Au750 and a J'ENCHANTE brand stamp. These markings are not limited to necklace clasps or chain ends. They are applied across our jewelry pieces in suitable positions according to each design.
What Does Au750 Mean?
Au750 means the jewelry contains 75% pure gold. This is the same gold purity level as 18K gold.
“Au” is the chemical symbol for gold. “750” means 750 parts out of 1,000 are pure gold. In simpler terms:
Au750 = 18K gold = 75% pure gold
The remaining 25% is made up of other metals, often called alloys. These alloys help improve strength, durability, and color tone, making the gold more suitable for fine jewelry than pure 24K gold, which is softer and more easily bent or scratched.
This is why Au750 is often used for necklaces, rings, pendants, earrings, and bracelets designed for regular wear.
Is Au750 the Same as 18K Gold?
Yes. Au750 and 18K gold describe the same purity level.
The difference is only the marking system. “18K” uses the karat system, while “750” uses the millesimal fineness system.
A simple way to understand it:
18K gold means 18 parts out of 24 are pure gold.
18 ÷ 24 = 75%.
75% equals 750 parts per 1,000.
So 18K gold can also be marked as Au750.
Depending on the brand, market, and manufacturing practice, you may see marks such as Au750, 750, or 18K. For J'ENCHANTE pieces, the material mark is Au750.
Where Can You Find Jewelry Hallmarks?
Jewelry hallmarks are usually placed on small, discreet metal surfaces. The location depends on the structure of the piece, because a necklace, ring, earring, and pendant all have different engraving areas.
On Necklaces and Pendants
On a necklace, the Au750 mark may appear on the clasp, chain end, or small metal tag near the closure. On a pendant, it may be engraved on the back, the bail, or another flat metal surface.
This is why many people search for phrases like “gold necklace clasp hallmark” or “18K gold necklace hallmark.” But the clasp is only one possible location.
On Rings, Earrings, and Bracelets
On a ring, the hallmark is usually placed inside the band. On earrings, it may appear on the back of the hoop, post, setting, or another suitable area. On bracelets, it may be near the clasp or on an inner metal section.
The placement does not have to be identical across all products. A good hallmark position should be readable enough for identification, but discreet enough not to affect the design or comfort.
Gold Hallmark vs Brand Stamp
A gold hallmark and a brand stamp are not the same thing.
Gold Hallmark
A gold hallmark tells you about the metal purity. For example, Au750 indicates 18K gold.
Brand Stamp
A brand stamp identifies the maker or brand of the jewelry. It connects the piece to its design origin, craftsmanship standard, and after-sales service.
For J'ENCHANTE jewelry, Au750 identifies the 18K gold material standard, while the J'ENCHANTE brand stamp identifies the piece as part of our fine jewelry collection.
These marks are small, but they help answer two important questions:
What is the jewelry made from?
Who made it?
Why Au750 Matters When Choosing Fine Jewelry
Au750 matters because it gives you a quick way to check the gold standard of a piece.
18K gold is widely used in fine jewelry because it offers a strong balance between gold content and daily wearability. It has a richer gold content than 14K or 10K gold, while being more practical for jewelry settings than softer 24K gold.
For many wearers, 18K gold can also feel more skin-friendly because of its higher pure gold content. In general, higher-karat gold contains less alloy metal than lower-karat gold, which may make it a better choice for people who are sensitive to certain metals.
However, “hypoallergenic” should still be understood carefully. Skin sensitivity depends on the full alloy composition, not only the gold percentage. If you have known metal allergies, it is always best to check the product details or ask the brand before purchasing.
A hallmark is useful, but it is not the full quality story. When choosing fine jewelry, also look at the setting, polishing, clasp security, comfort, diamond details, and how the piece feels when worn.
Does Au750 Tell You Anything About the Diamond?
No. Au750 only refers to the gold part of the jewelry.
It describes the metal used for the chain, setting, band, hoop, or pendant structure. It does not describe the diamond.
Diamond information should be checked separately. This may include carat weight, shape, color, clarity, cut, and certification when applicable.
For example, a lab-grown diamond necklace may have an Au750 mark on the gold chain or setting, while the diamond details are listed in the product description. Both pieces of information matter: the hallmark tells you about the metal, and the diamond specifications tell you about the stone.
How to Check a Hallmark Before Buying
Before choosing fine jewelry, start with the product description. It should clearly state the metal, such as 18K yellow gold, 18K white gold, or 18K rose gold.
Then look for the physical mark if possible. On delicate pieces, the engraving may be very small, so it may require close inspection.
A good hallmark should look clean, intentional, and properly placed. It should not interrupt the design, scratch the skin, or affect comfort.
You can also check the overall construction:
Does the clasp close securely?
Are the edges smooth?
Does the pendant sit properly?
Are the stones set evenly?
Does the piece feel balanced when worn?
Are the metal and diamond details clearly stated?
This helps you judge the full piece, not just the stamp.
How to Care for Au750 / 18K Gold Jewelry
18K gold is suitable for fine jewelry, but it still needs proper care.
Avoid exposing your jewelry to perfume, lotions, chlorine, cleaning products, or harsh chemicals. These can leave residue or affect the surface finish over time.
Store each piece separately in a soft pouch or jewelry box to reduce scratches. After wearing, gently wipe the jewelry with a soft cloth. For deeper cleaning, use mild soapy water and a soft brush, then dry carefully.
For pieces with fine chains, pavé settings, detachable charms, or moving parts, handle them gently and check them regularly.
Final Thoughts
Au750 is a small mark, but it gives you useful information. It tells you that the jewelry is made with 18K gold, a material valued for its balance of purity, durability, refined appearance, and everyday wearability.
Still, a hallmark is only the starting point. Before choosing fine jewelry, look at the full piece: the design, setting, finish, comfort, diamond details, and how it fits your lifestyle.
Explore J'ENCHANTE 18K gold lab-grown diamond Necklaces and Pendants, or visit our Materials & Diamond Standards to learn what to check before choosing your next piece.