What is the True Color of Aquamarine? How is it Heated?

OK, probably the most common misconception that people have is that Aquamarine should be just blue, usually they want dark blue. However, Websters dictionary defines Aquamarine as "a transparent blueish-green variety of Beryl. Blueish-green is the key phrase here.

I would personally define Aquamarine as being blue in body color with sea green highlights. I define Seafoam as being green in body color with blue highlights. I think these colors are gorgeous and I sell them quite well, mainly because most of the jewelers that I am dealing with never see these colors and they like something different, a lot of them do not even recognize these colors as being Aquamarine.

Almost all Aquamarine starts out life blueish-green and is heated to blue. Frankly blue is more marketable, at least commercially to the general public.

There is some material that does come out of the ground blue, heated by mother nature I suspect. I do not know if it is because all of the Aquamarine is heated blue and marketed that way, or if people just like blue better than the blueish-green variety. But you will probably get more requests for blue and sell it better to the general public.

Note: Times are changing though and I sell natural color Aquamarine very well. I prefer it unheated.

If you see some green in the Beryl you are looking at it is often a good sign that the material has not been heated. However, you cannot use this as a firm rule, because there are exceptions. Not all Aquamarine will heat and depending on the mine locality, even if it will heated it may not go blue or all blue, some green may remain. So having green in the rough is not a good indicator of whether the rough has been heated or not.

Note: There are some localities that will crack and break apart during heating and because of this are usually not heated. It is important that you know the locality of the rough and what you are doing.

I strongly recommend that you leave the heating to the experts. Besides the fact that most of the commercial Aquamarine is already heated at the mines before it reaches the market rough or finished anyway. You are taking a chance by heating unknown rough or if you do not know what you are doing.

Here is an example of what heating will do, before and after...

Natural Aquamarine Crystal - At left is a picture of a nice Aquamarine crystal that is natural and unheated. I would call this color closer to Seafoam than Aquamarine, it is definitely a little on the green side. I often cut this color I think that it makes a very nice and unusual stone.

Actually unheated natural Aquamarine is rather hard to find. It took me a while to get some material I could heat, so I could write this article.

 

Sawing Natural Aquamarine Crystal - I sawed the crystal almost in half, there was a slight flaw a little over halfway from the left in the picture.

You cannot heat anything that has a flaw of any kind in it. Heating a stone with a flaw, bubble, or, inclusion, will usually result in the flaw(s) spreading and becoming worse. Often if you see a sign or even a hint of a flaw there are problems that you cannot see and should not consider heating that rough. Because when you heat something like this, the flaws tend to grow.

Remember that there is often stress on the crystals that is not apparent and heating can cause cracking. Usually along the length of the crystal about a third to the middle of the thickness. Beryl crystals tend to crack lenght wise and because most Aquamarine is not all that big around to begin with, the yields and stone sizes go down dramatically when they do crack.

Note: Aquamarine is generally easier to heat than most other materials. That does not mean you will get what you want when you heat it though, often you will not get good results.

The thought that you can buy unheated Aquamarine rough at bargain prices and make a killing after you heat it.

Well, that is basically a myth, almost all rough dealers and miners know and do heat Aquamarine long before it gets to the market. Even if they know it will heat and for some reason do not heat it, the rough will bring the same price in either state, heated or unheated.

Everybody is aware that Aquamarine does heat blue and because blue brings better money in the general public market, you can count on almost everything being heated. In other words if the material is green/blue and somebody wants to sell it to you cheap, and then says it will "heat blue". Buyer beware, there is a reason that the material is still green/blue.

 

Left: Sawed natural Aquamarine crystal.

As you can see I cut it almost in half. I thought that cutting a crystal and heating half of the same piece was the best way to get an accurate comparison of what the heating will actually do the the color of the natural crystal.

Keep in mind that I know where this material was mined and that it will actually heat without problems. Generally, if I do not know this information I do not try to heat that rough.

 

 

Left - Is a comparison of the two pieces of Aquamarine after one piece has been heated.

Magic, it's now blue and looks a lot more like that color of Aquamarine that we are all used to seeing. The stone was heated at 400 C for an hour or so. As you can see the color change is fairly dramatic.

Notice that while it is now blue in color, the color itself is no more saturated than the original Blueish-green color of the natural crystal.

Heating changes the color, but does not darken it. In other words, if your Aquamarine is medium saturation before you heat it. It will be medium saturation after you heat it, although a different color (blue). You will not improve the overall saturation of the stone, just change the color.

Remember that you cannot always heat Aquamarine and that most rough has usually already been heated before you bought it (even if it looks greenish). If you do manage to find some unheated rough, I personally recommend that you think carefully before you try heating it to blue. Good reasons for this are.

Some of the natural true "Aquamarine" color material cuts beautiful stones, and you may be ruining a good thing by trying to heat it. Like I said earlier, I sell the natural color very well (look at the first picture, it is quite nice), and because almost all commercial Aquamarine is heated blue, I have something different, color wise and no competition.

If I had heated it blue then it is just ordinary Aquamarine and I am trying to compete (at least color wise) with commercial stones. I personally have better luck with unusual stones and I can generally get more money per carat for them.

Another good reason to not heat a stone is that any time you heat a stone (of any type) you are taking some risk of damaging (cracks/flaws, can make a nice sized stone you can cut before heating into small stones that you do not want to cut after heating) it and heating may effect the cutting process somewhat.

For example, heating might make the cleavage more tender (not on Beryl of course, but on say Zircons) or polishing harder. This is usually not a big problem, but it does happen.

Probably the biggest unknown is what color will heating the rough make it turn into? The rough may change colors, but be a better color before you heated it than after. This happens fairly often, heating can be unpredictable and you will not always get results that you want.

So think before you try to heat, then if you want to heat it anyway, good luck.

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