How Can I Tell if My Grandmother’s Vintage Diamond Ring is Valuable?

Often times we end up with the jewelry of now deceased family members. Sometimes lovingly handed down and other times simply by default.


Whatever the situation, you may be wondering how to tell if your jewelry is valuable. You may even be wondering what your options are when it comes to selling old jewelry for cash. You know that diamonds are valuable and that they retain their value forever. 

So, what are you going to do? Is a trip to the jewelers or a diamond buyer necessary to find out the true value of your ring?
Ultimately, yes, that may be the case.

But there are some tests you can perform yourself that will help you get at least a baseline.
I’ll cover the following topics:


1) Home Diamond Tests

2) Get the Help of an Expert

• Seek a professional appraisal.

Home Diamond Tests

Before you head off to one of the above-mentioned jewelers or diamond buyers, why not take some time to answer the question how can you tell if a diamond is real at home?
Here are the highlights first, then I’ll get into more detail.


First, you can check for marks on the diamond’s mount. That would be the metal that holds the stone in place. Then you can find out if you have a glass stone by checking the reflectivity of the stone.

What is the weight, density or size of your metal or stone? There are tests for that. And lastly, how to use a loupe to inspect your stone.
Okay, let’s break this down.

What Marks to Look For

If you’re thinking of selling old jewelry for cash, you clearly need to educate yourself first.


One of the first indicators of a quality stone is the quality of the metal it’s mounted on. A lesser value diamond or a fake diamond probably isn’t going to be set in expensive metal. And these rules don’t just apply to diamond rings.

You can use this method for any mounted stone, such as necklaces, bracelets, earrings and any other kind of jewelry.


The first giveaway is a C.Z. stamp. That tells you right there that your stone is actually a cubic zirconia which is just a fake diamond, in which case you can forget about getting any cash for your old jewelry.

However, if the metal is stamped with PT, Plat, 10K, 14K, 18K, 585, 900 or 950, your stone is set in either gold or platinum. And I’m going to assume you know which golds are more expensive based on the above numbers. If not, briefly, the K stands for carat and the higher the number, the higher the purity of the gold.


There are other markings you can look for, such as the designer's stamp or manufacturer’s logo, sometimes even the country of origin.

Do You Have a Diamond or Glass?

So, how can you tell if a diamond is real?
There are a variety of home tests that clearly aren’t scientific, but they might give you an idea. But honestly? Get a professional opinion.


The first test you can try is a fog test. And you don’t need to wait for a dreary, foggy day to try this. You can simply fog the stone with your breath, which is steamy.

If you note that the stone holds on to the fog for several seconds, your stone is likely fake. If it were a real diamond, the heat from your breath would immediately disperse, which would make fogging it up extremely difficult.


In the unlikely case where you have a black light laying around, you can also turn off all the other lights and hold your stone in front of the black light. Many—but not all—diamonds will give off a blue fluorescent glow under a black light. If it gives off another color, perhaps pale greens or yellows, this typically indicates your stone isn’t a diamond.


Again, please note neither of these tests is conclusive so they’re not the best way to get an answer as to whether your diamond is real.

Check the Weight of Your Diamond

Do you think Grandma might have left you some valuable vintage jewelry?
If you have things like necklaces or bracelets, there’s a fairly simple way to tell. Simply hold them in your hand and try to gauge the weight of them.

Even better, if you have a food prep scale in the kitchen, use that.
Platinum, gold, and silver are called “heavy metals” for a reason. Due to their density, they’re heavier than cheaper metals like brass and pewter.


Obviously, this test is only going to work if you have something comparable to weigh.

If you have 2 thick gold chains that are roughly the same size, and one is significantly heavier, the heavier one is likely the more valuable.
You can also check the weight of the main stone itself, simply by measuring it. For example, a 5mm diamond will equal .5 carat and an 8mm stone will equal 2 carat.

Use a Jewelers Loupe or Magnifying Glass

Still wondering how to tell if your jewelry is valuable? Here’s one last thing you can try at home.


Like the black light mentioned above, you probably don’t have a loupe laying around. But that’s okay. You can use a plain old magnifying glass.

Inspect your stone under the glass. Does it look perfect, seemingly without any imperfections at all? If that’s the case, don’t get all excited. It doesn’t mean you have a perfect diamond, because real diamonds have imperfections.

When a jeweler or gemologist talks about the inclusions in a diamond, they are referring to imperfections. If your stone has none, you don’t have a real stone. You have a perfectly manufactured stone.


You’re probably questioning the validity of some of these tests. And you should. So, what should you do?

Professional Evaluations – Online Diamond Appraisals

I know that old aged say if you want something done right, you should do it yourself. Trust me, that doesn’t apply here.

Sometimes you need a professional.

What if I told you there was a risk free, no-cost method for you to get an appraisal on your diamond rings—note the process is the same even if your thinking of selling vintage jewelry—and that this method not only provides you with the appraisal, it also offers you the means to selling old jewelry for cash?

There are many online diamond buyers, but iValue Lab will do all those things for you. They’ll cover the cost of a courier and insurance to their lab, where they will provide an appraisal and give you a cash offer. If you accept their final offer, you get your money within 24 hours.

Worried about security? The entire process is recorded, right from the time they initially open your package.

There’s no need to hesitate. Get your risk free jewelry appraisal now.

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