Buying a Gemstone: The Right Questions to Ask

Review gemstone jewelry before buyingWhether you are in the market for a fine ruby or an amethyst, there is a lot to know before finalizing a gemstone purchase. How can you be sure of what you are getting? Are you aware of the different gem treatments that can alter the appearance of a gemstone? Some treatments will greatly affect a gemstone’s value. Here you will find answers to your questions about gemstones as well as the types of questions that you ought to be asking!

what are Common Enhancements to gemstones?

Gemstones come out of the ground as a rough crystal. They are cut and polished to reveal their beauty. In addition to lapidary (gem cutting) many gemstones are routinely subjected to treatments that enhance, improve, or radically change their appearance. A reputable gemstone dealer should always reveal the types of treatments that a gem has undergone. This is an important fact for you to consider. Natural untreated gemstones can be very rare, in some mineral varieties all but impossible to find. If someone is offering to sell you a natural untreated gemstone, this will certainly be reflected in the price. Here are some explanations of some of the more common gemstone treatments.

  • Heat treatment: A common gemstone enhancement, heating a stone can vastly improve its color. Rubies and sapphires that would otherwise be worthless can fetch hundreds of dollars per carat once they have undergone heat treatment. Heat treatment is all but routine in many other types of commercial gemstones such as amethyst and citrine. You may find that the color of heat treated gems will fade after a long period of time if the gemstone has been regularly exposed to direct sunlight.
  • Irradiation: Irradiated gemstones have recently been regulated by legislation in the United States. Bombarded with neutrons or electrons,irradiated gems are controlled by delayed distribution to make sure that they are not radioactive and safe to wear. Irradiation can vastly change a gemstone’s color. Blue topaz is a prime example. Topaz is found in nature in a variety of colors from white to golden, but blue is not one of them. Nearly all blue topaz achieves its vivid blue color through irradiation.
  • Fracture Filling: When a gemstone has surface-reaching inclusions, filling the cracks and crevices with a foreign substance can dramatically improve a gemstone’s appearance. Currently, thousands of different fracture filling material is in use. Fracture filling is not a permanent treatment and can be removed by professional jewelry cleaning devices, particularly the ultrasonic machine and high pressure steamers. Emeralds typically undergo fracture filling treatments because emerald crystals are frequently highly included.
  • Diffusion: A diffusion treatment involves heat treatment with additives. The additives can vastly change to color of a gemstone to something other than its original color. Lattice diffusion is of particular concern because an element is introduced directly into the crystal structure of the gemstone, which changes its physical composition as well as its appearance. Lattice diffusion is also difficult to detect and is not considered an acceptable treatment by many reputable gem dealers.

Country of Origin

Inquiring about the gemstone’s country of origin is of particular importance if the seller is representing “fair trade” gemstones. Currently, there is no official certification for fair trade in the gemstone industry. By asking about the “chain of custody”, you are asking the seller to reveal to you where the gemstone was mined, where it was cut and polished, and (if applicable) where it was set into jewelry. If a gem seller is representing “fair trade” gemstones, they should have ready answers to these important questions.


If a gem seller offers you an appraisal to accompany your gemstone, ask if the appraisal is done by the seller or by a third party. Appraisals are most often used for insurance purposes and represent a fair market price that a buyer would expect to pay for the goods described. A gem seller who is offering to sell you a gem and promises that it will appraise far higher than the selling price should be able to provide you with an appraisal done by someone who does not benefit from the sale of the gemstone. If you are getting an appraisal with your gemstone purchase, make sure to ask that the appraisal be done by a third party.

how to Buy gemstones With Confidence

Ask what the seller’s disclosure policy is on gemstone treatments. Many commonly accepted treatments get lumped together under the blanket term “enhanced.” Don’t be intimidated! Be specific. An educated customer should be welcomed by a knowledgeable gem dealer. Did you recently purchase a gemstone? What questions did you ask before finalizing your purchase? Were you happy with the answers? Tell us.

Read more posts from the Gemstone Buying Guide series