Heat treatment and irradiation in crystals is not a new phenomenon. We have all seen in the market heat-treated amethyst disguised as bright-orange citrine and quartz that has been irradiated to a dark brown, sometimes black, color. However, the process of artificially enhanced minerals has been fine-tuned in recent years, and now, minerals with deepened colors appear less extreme and rather "natural," even to mineral experts. Artificially
Natural fluorite and quartz from Zhejiang, China
As a collector and seller of Chinese minerals, I became curious about some of the “new” finds coming from Zhejiang, Fujian, and Xianghualing and wondered if I could get some straight answers about this material that has been widely circulating among crystal sellers. I asked a trusted Chinese dealer with whom I've done business for years to (1) select two fluorite and quartz pieces from the Zhejiang locality and (2) have them both irradiated to affect their colors. Below are videos showing each specimen before and after irradiation.
Fluorite and quartz from Zhejiang, Fujian, and Xianghualing in China is often color-enhanced by irradiation, because the resulting intense blue of the fluorite is perceived to have a more appealing aesthetic as compared to its ordinarily clear to pale green hues. One factor that is commonly considered when determining whether a specimen has been treated is the color of the surrounding quartz. Quartz from these specific Chinese localities is typically clear or white. So, if the quartz is a dark and smoky (and the fluorite, blue), it is quite possible the specimen has been irradiated.
White quartz with slight phantoms from Zhejiang, China
Artificially treated / irradiated smoky quartz from Zhejiang, China
But there’s no surefire way to confirm whether irradiation by human processes has occurred, at least not by simple examination. In fact, the results of the mineral tests I received can only confirm with certainty what minerals make up the specimens being tested: fluorite and quartz. Whether artificial irradiation has occurred, as mineralogist Al Falster of the Maine Mineral & Gem Museum has told me, can be very difficult to detect.
Just because the test can’t detect for artificial irradiation, however, doesn’t mean it hasn’t happened. Below are examples of fluorite that have been artificially enhanced, as provided by my vendor. As you can see, these examples display a much deeper and more intense color variation.
Natural smoky quartz with colored fluorite does, of course, exist, as seen in France and Switzerland, as well as from the Tongbei Mine in Fujian (notably in association with spessartine garnet). In fact, blue fluorite in association with smoky quartz has been found in Kazakhstan and in Colorado, but as I’ve been told by a reputable dealer, it’s quite rare and coveted among collectors. But as the look of glassy blue against rich smoky brown is trending on a rise with customers, and as a new vein of regular white quartz with pale green fluorite has become abundant in the market, this material is a prime target for artificial enhancement.
Shown above is a variety of specimens from other vendors who claim their colors are completely natural. As you can see, these pieces share a remarkable resemblance to the ones in the video that I sent to be irradiated.
Fluorite and Quartz piece I had a dealer irradiate for this experiment.
This post is meant only to be informative and is by no means a judgment against a customer’s or seller’s choice to purchase irradiated minerals. If you love the way they look, go for it. But shop with an awareness of current vendor and mining practices and trends in the marketplace, especially with all the “new finds” we read about online.
Thank you to my Chinese minerals dealer in Donghai for providing samples of before and after irradiation, to Emily at The Faceted Fern for the connect to Al Falster at the Maine Mineral & Gem Museum, and Bettina Chin Cho for editing this article.
