Buying Amethyst Gemstones: Synthetics, Quality, and Treatment of February’s Birthstone
Shopping for colored gemstones can be fun, and with amethyst, there are so many shapes, styles, and forms out there–faceted gemstones, cabs, carvings, crystals, beads, and objects–that your choices are virtually limitless. But gem buying can be fraught with anxiety, too, knowing that treatments, synthetics and imitations are out there. No one wants to be taken.
First let’s look at quality.
ABOVE: This 11.35 carat medium-toned amethyst is remarkable for its stunning cut. Photo Mia Dixon. Courtesy Pala International.
Amethyst: Quality of Gemstones
As with any colored stone, you’ll want the best color, the best cut, and the best clarity you can afford. That said, however, there are some considerations.
First, best color. The jewelry industry considers “best color” to be those that are the most intense without approaching black, and purest in tone or value (without overtones of brown or gray). And they price accordingly. However, the industry view of “best color” and your personal view of “best color” might be wildly different. When it comes to amethyst, you might be enchanted with the light-toned lavender color of Rose de France gemstones while a dark, highly saturated “Siberian” amethyst leaves you cold. Buy the gemstones you love, not what someone tells you is best. You are the one who will wear it after all.
Second, best cut. Never skimp on this, especially not to save money. Once you see a well-cut stone, you’ll always regret the poorly cut stone you bought. The cut of a stone–especially a faceted stone–makes all the difference in the world between “blah” and “KAPOW!”
Third, best clarity. This, too, can be a matter of preference to a certain degree. Some gemstones are naturally more included, like emeralds or rubellite tourmalines. Unless you have bags of money, color is primary on these stones and a certain level of included-ness is expected. However, amethyst naturally occurs in very clean crystals. Faceted stones and cabs, high-quality carvings, or a crystal you intend to wear as jewelry should be as clean as possible. There may be a few delicate inclusions that are not visible to the unaided eye, but amethysts should never have the level of inclusions in them that you’d expect of an emerald or rubellite. In objects, however–things like boxes or spheres–and in beads, inclusions that cloud the amethyst to the point of translucence may be expected or even desirable. Here you’re looking for the quality of the cutting and the overall effect of the piece.
Amethyst: Treatment of Gemstones
When it comes to treatment, amethyst gemstones are largely untreated, though some very dark stones may be heated to lighten the color. Heating can also remove brownish inclusions in amethysts. Heating certain types of amethyst will convert them into citrine.
About Synthetic Amethyst Gemstones
Synthetic gemstone materials are everywhere in the world of industry, from lasers to medical equipment to the quartz watch on your wrist. (Or at least, the quartz watches that used to be on wrists.) Naturally, a lot of this material has come into the gem market, some of it openly and honestly and some less openly and honestly.
Synthetic amethyst is somewhere in between. Those in the jewelry industry know there is a lot of synthetic amethyst out there. (Some estimates are that up to half of the amethyst sold is synthetic.) It’s one of those “open secrets.” The problem with this is that most buyers have no idea.
If this were ruby or sapphire, there would be all kinds of stories in the trade journals and in the general press. But this isn’t true for amethyst. The reason is two-fold.
First, cost. Most amethyst on the market runs a few dollars a carat. Even the finest amethyst gemstones can be found for probably under $50 a carat. Compare that to the thousands to tens of thousands of dollars a carat that the finest rubies or sapphires cost. If you’ve paid $10 for a stone compared to $10,000, your outrage at having purchased a synthetic will probably be considerably less. (Or maybe not.)
Second, detection. Unless an amethyst has the distinctive inclusions of the synthetic, it is almost impossible to distinguish between synthetic and natural amethyst by normal gemological means. The difference can be identified by infrared spectroscopy in a fully equipped lab such as the one at GIA. But clean stones can’t be distinguished by your neighborhood jeweler. (There is some information on the internet that indicates a novice can distinguish between the two by holding the stone to the light. No. Period.)
Synthetic Amethyst Gemstones: To Buy or Not To Buy
If you are concerned about whether the gemstones you’re buying are synthetic or not, you have three options.
First, you can ask the seller to show you the inclusions in the stone, under a microscope, that prove the stone is natural. A competent gemologist should be able to do that. However . . .
Second, a lot of amethyst is pretty clean. In that case, you can ask for a written guarantee that the stone is natural. Be aware, though, that the merchant him/herself may have bought the material in good faith and believes that the gemstones he/she is selling are natural.
Third, you can ask for the stone to be sent to a gemological laboratory for verification and a colored stone report (known colloquially in the trade and beyond as a “cert,” short for certificate). A quick look at the GIA Laboratory fee schedule will show you that for stones between 20 and 50 carats, a colored stone report is $85. It’s $85 even if the stone is identified as a synthetic. Are you going to do that for a $100 stone? An $800 stone?
Only you know the answer to that.
Buying Amethyst Gemstones
Bottom line: Always ask if you’re unsure. (It’s always a good idea to ask if gemstones are treated, and if so, how, and if they are natural or synthetic.) If the answer is “natural,” and you’re still not sure, you can always walk away if the money involved is significant enough to you. Or you can decide that the price is commensurate with the beauty of the stone regardless of what it is, and that you are willing to pay it.
Buy what you like. Buy the best gemstones you can afford, never skimp on cutting quality, and chances are good you’ll love it forever.
Sharon Elaine Thompson is a GG and FGA who has been writing about gemstones and jewelry for Lapidary Journal Jewelry Artist since 1987. She also writes a line of birthstone romance novels under the name Liz Hartley.