Natural-color citrine is rare, so it's best to assume that any citrine is heat-treated. In some cases, colorless quartz with yellow dye may imitate citrine. In fact, heating amethyst produces most citrine, in strong yellow or orangey hues, while heating smoky quartz can produce lemon-yellow hues. Since natural-color citrine is rare, most of the material on the market has undergone treatment. There are no known treatments for chrome diopside. In addition, heat treatments can improve the color in certain stones.Ĭhalcedony can also receive coatings, sometimes only on the back of a cabochon. So, check any brightly colored samples carefully. Chalcedonyīleach and dye treatments are common in chalcedony. However, some stones may contain oil or dye, and others may undergo radiation treatment to improve their color. Cat's Eye (Chrysoberyl)Ĭat's eye stones rarely receive treatments. With aquamarine, it's best to assume heat treatment. Read more about aquamarine heat treatment. This undetectable procedure reduces its yellow hue. Nearly all the aquamarine on the market today has undergone heat treatment. Some ametrine may be heat treated to create the citrine half, but this procedure is undetectable. Ametrineįor pieces with both purple and yellow saturated colors, check for dye treatments. In other cases, purple dye in colorless quartz creates the observed color. However, this undetectable procedure is rare. Some amethyst undergoes heat treatment to lighten its color. Reconstituted gems often exhibit a mosaic structure, which may only be visible under high magnification. Artificial resins as well as copal may also be added to the mix. In some cases, the people creating reconstituted pieces add modern insects to the mix. Reconstituted amber consists of several pieces pressed or melted together. Image by starbright from Pixabay.įor dye treatments, look for color concentration in pits and fractures and uneven color distribution.
The fracture spots in this piece of amber are evidence of heat treatment. Heat treatments darken the color and leave "sun spots." These spots appear like glitter within the stone. Coatings and fracture fillings are less common. AmberĬommon treatments for amber include heat treatment, dye, and reconstitution.
Some stones may have oil-filled fractures similar to emerald oil enhancement. Concentrated color in cracks and fissures is a good indicator of dye. AgateĬolorful specimens of agate are likely dyed. If you're unfamiliar with gemstone treatments, check out our articles on heat treatment and radiation treatment, two of the most common gemstone treatments for enhancing color. As a gemologist, trader, or consumer, you'll want to know the most frequently used treatments so you know what to look for and what questions to ask before purchasing or working with gems. Much of the gem material currently on the market has been treated in some way before it reaches the consumer. Humans have treated gemstones for thousands of years. Photo courtesy of and Simrit Collections. Otherwise, you might miss something that can affect their value. If you're sorting through a mixed lot of gems, keep these common gemstone treatments in mind. Keeping track of them can be difficult! This article briefly lists the enhancements commonly found in the most popular gems. Learn about these common gemstone treatments and print out our handy reference sheet. In today's gem trade, treatments are almost ubiquitous.
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