I had a very nice young couple in looking for engagement rings the other day. I liked that both of them came in together because it ultimately means that the young woman will get exactly what she wants. Well almost…..She wanted an engagement ring with an emerald set in it. I get these requests a few times per year and it’s always a bit disappointing for the purchaser when I have to tell them about the risks of emeralds in rings.
Gem materials are described by gemologists as gemstones when they have beauty, rarity, and durability. Some of these three descriptions are a little challenging today. I have seen quite a few gemstones that the word beauty is a bit of a challenge for. With modern mining techniques it seems like there is an endless supply of gem materials, especially diamonds, although this is not actually true (it takes mining one ton of rock to end up with 1 carat of diamond and some stones, with tanzanite as a prime example, being effectively mined out of existence in a generation or two). Durability is an even trickier issue because gems like opals are certainly beautiful and rare (well the finer ones are) but they are quite fragile as gemstones go. And this durability issue is the problem I want to discuss today.
When customers come to me and say they don’t want a diamond in their engagement ring (and many do—let’s not forget Princess Diana’s large sapphire ring) I routinely tell them that I only recommend diamonds, rubies and sapphires for engagement rings because they are the most durable of the gem materials. This doesn’t mean you can’t scratch or break them at all, as anything worn every day of your life will tend to get banged around quite a bit, but it does mean that they have the highest hardness of the natural gem materials available to us. Fortunately sapphires come in a wide variety of colors including blue, pink, purple, orange, yellow, white, black (as in star sapphires) and a pretty ugly green (we’ll get back to that in a minute). When corundum (which is what sapphire and ruby are) is red, it’s a ruby; so it’s the same gem material as sapphire but it’s called a ruby when it’s red.
Emeralds are actually a fairly hard gemstone when measured on the Mohs scale of hardness. Diamond is a 10, corundum is a 9 and beryl (the gem family that emerald is from) is approximately an 8. The scale, however, is not what it seems. The differences in numbers only reflect which next harder material will scratch the one below it. The relative hardness is quite different. Diamond is approximately 90 times harder than sapphire. There is also some variation within the same material. Aquamarine, another member of the beryl family is a true 8 on the scale but emerald comes in closer to 7 1/2.
So part of the problem with emerald as an engagement ring (or any every day wear ring) is that the hardness simply isn’t high enough to take normal daily abuse. However there are two other problems with emeralds. Almost all emerald material is at least lightly included and much of it heavily included. This is called “jardin” (French for garden) sometimes, in an attempt to glorify what would be completely unacceptable in other gem materials. All of these inclusions in emeralds tend to mean the stone is much more fragile than other gem materials. However there is an additional problem. Emerald is routinely treated with either oil or various fracture filling substances in order to hide the inclusions. Oil, and some of the fracture fillers, can leach out over time simply due to normal wearing (washing hands, exposure to cleaning chemicals, etc.), or due to regular cleanings at your favorite jeweler. (For more on gemstone treatments please see this article andthis one.) This will mean that the look of the stone can change over time as well, so one day you look down at your pretty stone and say that’s not the beautiful gem I remember!
Okay, you say, I won’t get an emerald so surely there is another green gemstone that is more durable! Well easier said then done. There really isn’t any other gem stone that has a real emerald color. Tourmaline comes in a range of striking greens (although not the same green as emerald) and greenish blues but tourmaline has a scratch hardness lower than emerald. My wife has a tourmaline engagement ring. It started out at 10.50 ct. and we’re down to 9.50 ct. after repeated repolishings to clean up the stone after she scratched it. She now only wears it occasionally (but fortunately, because she’s MY wife, she has a multitude of other rings to wear on that finger). Another customer of mine who insisted on a tourmaline (despite an onslaught of warnings from me) just had to have her stone repolished after only a few years of wear. There was literally nothing left of the top facets on the stone. There are, as I mentioned above, green sapphires, but the color of the green leaves a little something to be desired as it tends towards a paler, lime like green with tinges of blue in it. More durable yes. As pretty, no.
So if you want an emerald in your engagement ring, just be prepared to replace it occasionally. Fine emeralds, however, can be very expensive stones so it can be quite a hit. Or you could get a ring with a number of smaller emeralds in it. That way at least, if you should have to replace some, it won’t cost you quite as much.
The ring pictured above is a sapphire and diamond engagement ring with a natural color (unheated) blue sapphire.
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