When colored gemstones are treated artificially, we say that they have been enhanced. Most colored gemstones have been enhanced. Stones may be treated while still in their rough crystal form or after they have been cut into polished gemstones. Colored stones are enhanced for four reasons:
- To intensify, deepen and/or make the color more uniform
- To remove a modifying color, leaving the rarer hue more visible
- To mask or eliminate unsightly inclusions
- To stabilize the structure of the gemstone
All treatments of colored gemstones must be disclosed to the buyer, so consumers can make informed decisions about the value of their stones before they purchase. All enhancements affect the cost of colored stones, some by a little, others by a lot. Because most colored gemstones are enhanced, those that are not command premium prices.
There are many degrees of enhancements. Some alter color just a bit, while others are so extensive they create almost the full color of the polished gem. Some mask only a few unsightly inclusions, while others “burn out” an entire field of internal markings, leaving the stone nearly flawless — something that is fairly rare in nature. any enhancements can be detected by experienced gemologists with standard laboratory tools. Other enhancements require advanced laboratory identification. Some enhancements are permanent; others are temporary, allowing a strong color to fade or inclusions to re-appear under certain circumstances. Your jeweler can provide an independent laboratory document identifying any enhancement to the stone. This is especially important for the purchase of an expensive ruby, emerald or sapphire. Customers should understand how this enhancement affects a stone’s quality, current cost and potential future value, especially if the treatment may not be permanent.


