I found this shiny thing…


We hear it a lot. You pick up this ring under the cushions of an old sofa, or in a box of things that once belonged to your great-great aunt. It’s shiny yellow or white, kind of old, and has one, two, three maybe more clear stones. They could be diamonds. Is it the real thing?

Here are some tips to help you divide costume jewelry from fine jewelry:

  1. Check for markings

    Sometimes small engravings are visible inside the band of a ring that can help you determine its quality. Just for the record, they’re not reliable 100% of the time – because it can always claim to be something it’s not. Mostly however, stamps are a pretty good indicator of the metal used.
    10K and 14K of course stand for 10 or 14 karat gold. This can be yellow or white (white gold has a finish of the precious metal rhodium that gives it a brilliant silver look).
    “925” is the same as sterling – that stands for 92.5% silver content.
    “585” is the same as 14 karat gold.
    “HGE” means “heavy gold electroplate.” It’s not solid gold.
    “GP” stands for “gold plated” but the actual gold content is almost nonexistent.
    “GF,” or anything with a fraction, stands for “gold filled.”
    – No marking at all? Costume jewelry often bears no markings. Karat gold & sterling silver are required to have quality stamps, but they can wear off, so when in doubt it’s best to have it tested by a jeweler.

  2. Check the finish

    If you see lots of corrosion (especially inside the ring), pitting, and patches of color that aren’t on the rest of the surface, chances are high that it’s not a gold setting. It may just be a finish wearing off, exposing the base metal underneath. Silver may turn black with tarnish over time, but gold will not.

  3. Check the stones

    In most cases, the stone in question is potentially a diamond or a cubic zirconium. Commonly nicknamed “CZ’s,” these manmade stones are used as diamond simulants in all kinds of jewelry (even some fine jewelry on occasion).

    So you think it might be a diamond? Keep this in mind:
    If the ring is sterling, chances are it’s not set with a diamond. Sterling is not a good setting for fine diamonds, so it’s usually seen with CZ’s, or many very small diamonds – not larger, rarer & more valuable diamonds of quality.

    Diamonds taken from the earth all carry Mother Nature’s fingerprints. Manmade stones are perfectly cookie-cutter, inside & out. Looking through them is just like looking through glass. CZ’s tend to reflect color like a prism, while diamonds shimmer and disperse light like fireworks, almost as if they shine from the inside. If you have a large clear gem lacking any trace of internal characteristics, it’s probably not the real deal. Outstanding clarity doesn’t mean it’s not a diamond, just keep in mind that a truly flawless diamond is astronomically rare.

    You’ll want to bring your jewelry to a certified jeweler to rule out the possibility that your gemstone is a white topaz, white sapphire, or another colorless jewel – or even a manmade diamond or moissanite. These are major factors in determining the value of a genuine stone.

  4. What if it scratches glass?

    This urban legend comes from the fact that diamonds are the hardest substance known. The logic says that if you can scratch glass with it, and it remains unscratched, it must be a real diamond. However there are a lot of substances, including gems, that are hard enough to scratch glass without being damaged. So skip the scratch test and use the other factors to make a judgment call.

If you examine the ring & the evidence stacks up in its favor, a qualified jeweler can run quick tests to confirm it. If you believe it’s jewelry of value, you may consider having an appraisal done to determine an appropriate replacement value if your find turns out to be the real item.

Questions about grading, appraisals, or diamonds & gems? E-mail us (or stop by the store if you’re in the area). We are an IJO Master Jeweler, independently owned for over 25 years, with a certified bench jeweler, master appraiser & gemologist on staff. We’ll be happy to help!

You may find these helpful:

What are the markings on my jewelry?

Hallmarks on Old Jewelry

Why is gold in different colors?

GIA Guide to Gemstones in 7 Steps

Jewelry: The Real, the Fake, and the Rest

The 4 C’s of Diamonds