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Heres how to upgrade the center diamond in your engagement ring

It’s time for an upgrade!

As we go through life, we upgrade everything; our home, our cars, our family, our possessions, our careers

And for most, a bigger diamond!

If that’s on your bucket list, you’re not alone. Many women get to the point in their lives when their original diamond just won’t cut it.

It isn’t Big Enough!

Maybe you’d like a diamond that represents your position in life now. Maybe you’d like to upgrade because you have the means (the kids have moved on). Maybe it’s a big mile-stone anniversary coming up…

Whatever it is, it’s time to enlarge!

So let’s do that. Let’s go over the 5 basic steps to upgrading the center stone in your engagement ring or wedding set. Because there are plenty of things you should consider…

1) The Millimeter Size

This is one of the biggest concerns. Because if you get this wrong, you’re spending money for nothing. It’s not even worth it!

When we’re talking about diamonds and sizes, you have to realize that diamond carat weight and diamond millimeter (mm) are two different things. The carat weight is how much the diamond weighs; i.e. half carat, quarter carat, 1 carat… But diamonds can be like people, some short and fat, some tall and skinny. So putting them side by side could look totally different (and still weigh the same).

Carat weights vary greatly when it comes to how the diamond is proportioned. Take for example two nickles stacked on top of each other. That’s worth 10 cents. But if you put a dime next to them. The dime will appear smaller, yet it’s the same value. So just because two diamonds are the same weight, doesn’t mean they’ll face up the same.

Millimeter on the other hand, is how wide the diamond is (from one side of the girdle to the other). If you measure your diamond with a diamond gauge, you’ll get the appearance size from a face up position (which is how you look at the ring). That’s a better indication of size. Because you can tell the difference between a nickle and a dime. One’s bigger. Obviously. It’s quite noticeable. And that’s the goal for today… To get a diamond that’s noticeably different (regardless of actual weight).

Measure The MM Width Of Your Diamond
Some 1 carat diamonds are cut shallow and spread (meaning they look much bigger than they really are). Some 1.25 carats are cut lumpy and deep (meaning they look much smaller than they are). So when put up against each other, these two stones may appear the same… Or very similar, as in this photo below…

Two Different Diamond Carat Weights Similar In Appearance And Size

All stones have a mm width. That’s what you should use to upgrade (not the carat weight). And all weights have a standard mm width according to industry guidelines (if the stone is cut properly).

Standard MM Diamond Sizes

Knowing if your diamond is close to standards can help you decide which carat weight is right for you. Because if you spend $3,000 for a new diamond, and it doesn’t look any bigger (meaning no one will notice), then it defeats the purpose of an upgrade (unless you only want to upgrade quality).

The diamond mm can be found on any diamond report (aka certificate)…

Diamond Millimeter on a Diamond Report Certificate

If your stone isn’t certified, then buy yourself a diamond mm gauge here, or just go into a jewelry store and ask them to measure your diamond.

Now that you know how big your diamond mm is, you can now look at a diamond that’ll appear bigger to the eyes. Also note that you don’t always have to stick with the same shape either. You can venture into Princess Cut, Oval Cut, Radiant Cut, Cushion Cut…

Generally you’ll need to go up about 10% or bigger in mm size, in order to see a visible difference. Otherwise, it may look to similar. See below…

Compare Diamond MM Sizes

This chart gives you a better idea of decent step-ups and the prices involved (all diamond prices are an average at the time of this post, and come from James Allen here).

2) Will it Fit?

You can’t just pop out one diamond and insert another. It doesn’t work that way. Especially when you’re going mucho grande.

For the thing that holds in your stone; the head, basket, or prongs, will have to be upgraded too.

You’ll need to make sure that your old ring will accommodate that bigger head or basket. If not, you’ll have to upgrade the ring as well. No way around that.

Plus, many rings have the prongs or head built-in. Meaning you can’t pry them open to fit in a bigger diamond. Some mountings are just made to hold one specific size. Look at the examples below, of rings that can’t be upgraded, and rings that can.

Rings you cant upgrade the center diamond

Mountings you can upgrade with a bigger diamond

3) Is the Ring Balanced?

Sometimes rings look odd or funny if too big of a stone is placed on top (also realize that bigger stones will set up higher in the mounting too. You’ll bump and hit it more often – so make sure you update your insurance policy as well). It may throw off the balance and symmetry of the entire mounting. Like these exaggerated examples below…

Balance the diamond size with the mounting

Granted, those are fairly large diamonds I’m showing, but it’s all to make a point. Larger diamonds normally demand a little bit bigger mounting in order for them to look like they belong together. It all comes down to opinion though… If it looks visually good to you, and you don’t mind the size difference, then that’s all that truly matters.

4) Quality: Color and Clarity

You can’t go too extreme with your choice of center diamond quality if you have diamonds in the mounting as well. Most engagement rings or wedding sets do have side stones. Those diamonds have a color and clarity too. So if they’re yellow, or cloudy, or dark, then putting in a much nicer, better color, brighter center stone may look unmatched.

Try to match the center diamond with the side diamond color and clarity

A good rule of thumb is to try to get a similar quality center stone, so that they compliment each other. Or at the very least, go one step up. One step (one grade) is hard for anyone to notice.

But… And here’s a BIG BUT…

When you get into bigger diamonds, the stone gets large enough where you can see inclusions and color easier. This is true for all shapes of diamond. Going from a .33 carat to a 1.00 carat will be a big visual difference. You may see flaws in the stone. You may notice the color easier… All good things to consider. You may have no choice but to step up to the next level of color and clarity, just so you don’t see black carbon spots in the stone.

Granted, you can always upgrade the side stones too… Make them better. If you wish.

5) Cost

Upgrading isn’t cheap (as you saw above).

Some think turning in a smaller stone for a larger, would only cost them a couple of hundred


It’s usually a couple of thousand. Diamonds and size normally double and triple in price as you go up (regardless of quality). So you may have to pay just as much for a 10% mm upgrade, as you did your entire wedding ring.

It’s Sticker Shock!

Plus, the price of diamonds now, versus what they were back in 1970 are totally different. Day and night. So be prepared for a hefty chunk of change (but really no different than when you upgraded your home, car, or that new jet ski you just bought…)

Look for sales, discounts, and interest free financing to soften the blow.

And always check with James Allen or Blue Nile before you decide to buy.

James Allen

Blue Nile

(And YES those are affiliate links)

Buying online can actually save you TONS of money (compare their prices with mall stores and you’ll see). So for the same price, you could actually get a much bigger and nicer center stone (and GIA Certified) too.

I highly advise checking them out.

And I also recommend a decent quality of SI1, G-H+, Ideal Cut, just so the stone faces up well (no visible flaws). With their huge inventory, beautiful warranties and low prices, I’m sure you’ll find the perfect stone for you.

It really is the best way to go when upgrading!

Enjoy your BIGGER diamond, and if you have any questions, or need some help deciding on a stone, drop me a line and let me know.

Cheers! :)

Recommended Jewelry Supplies:

Ultrasonic Jewelry Cleaner Jewelry Steam Cleaner Complete Jewelry Cleaner Kit Diamond Dazzle Stick
Gold Silver Jewelry Polishing Cloths Jewelry Making Supplies Kit Gold Acid Test Kit Watch Tool Repair Kit
Ring Adjusters EMT Emergency Ring Cutter 10x Jewelers Loupe Jewelers Microscope

Recommended Jewelry Supplies:

Ultrasonic Jewelry Cleaner Jewelry Steam Cleaner
Complete Jewelry Cleaner Kit Diamond Dazzle Stick
Gold Silver Jewelry Polishing Cloths Jewelry Making Supplies Kit
Gold Acid Test Kit Watch Tool Repair Kit
Ring Adjusters EMT Emergency Ring Cutter
10x Jewelers Loupe Jewelers Microscope

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