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Step 1
Shop only reputable gem dealers, whether they're doing business at a retail shop location or on the Internet. Look for certified gemologists specializing in sapphires, jewelers affiliating with gemstone trade associations, those with long-standing reputations in your community, and, in particularly, those referred by people you know and trust.
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Step 2
Decide whether you want natural or synthetic (also referred to as created or cultured) sapphires. While these stones have been around long enough to be mentioned in the Bible, synthetics didn't appear on the jewelry scene until around 1902, when scientists working on gem replication formulas came up with the "verneuil process." The science of culturing synthetic star sapphires continues to this day and has been so refined that only those having gemology credentials can distinguish between artificial stones and the real thing.
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Step 3
Look for crystal clarity, hardness and size in addition to color and shape when you choose your stone. Star sapphires are usually cut in a dome shape, but shoppers searching for unique shapes have hyped the demand for ovals and rounds. Use your budget as a guide for determining the carat weight of the stone you seek to buy. Like diamonds, star sapphires are graded in carats.
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Step 4
To help you choose your stone, ask where your star sapphire was mined. Thailand and Australia are both emerging sources, but if you're looking for a jewel that originated at the epicenter of the oldest sapphire mining system on earth, you'll want a gem from Sri Lanka. Sri Lankan Kashmir star sapphires are rare and expensive, the best-known product of color zoning, a natural process that takes centuries to complete, since growth layers of crystal create the uniformity of color and clarity that produces the purest blue stone on earth.
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Step 5
Find out if your star sapphire was subjected to heat treating after the stone was mined. Heat-treating pumps up and enhances the crystal properties of the gem so it develops a more intense shade of blue. Don't discount a stone that has been heat treated; treated sapphires wind up with more clarity because tiny particles of matter are eliminated, making the star facets more pronounced.
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Step 6
Seek out rare types of sapphires so your gem stands out from all others. For instance, color-changing sapphires may look blue in natural light and violet in artificial light. Color-changing sapphires with six or more star prisms are rare, so you'll pay top dollar for them. If you're offered a color choice, ask for Kashmir, or cornflower blue, stones. Of course, you might want to opt for pink, red, orange, green, yellow or other colors--such as the yellow star topaz, which is considered a sapphire by gemologists. Expect the selling price to increase when you select rare colors and more than six star cuts.
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Step 7
Exercise caution by covering all verification bases. Inspect your sapphire picks under a microscope, ask for a jeweler's loupe to get a closer look or call in an expert to give you a second opinion about the star sapphire's value if you have doubts or don't quite know what to look for. Don't wait for your postpurchase appraisal to find out that you've bought a stone worth far less than you paid. If the gem seems too good to be true, it probably is.
