Updated: Jun 3, 2019
When purchasing a blue sapphire gemstone the key factors one must consider are color, cut, clarity, and carat weight.
1. Color is the most important factor when searching for the right sapphire. The main points when choosing a blue sapphire based on color are its hue, tone, and saturation. The ideal color hue of a blue sapphire is of one having a primary shade of blue.
2. The tone indicates the depth of its color, which can range from black (the deepest) to almost colorless (the shallowest). The ideal tone for a sapphire is medium. The saturation measures the color intensity, with ranges from “strong” to “vivid” saturation. The ideal saturation for a sapphire would be one that is vivid.
3. When choosing based on cut, one must realize that sapphires, like all gemstones have no particular “ideal cut,” like that of a diamond. Blue sapphires are also cut differently. They tend to have greater depth than a diamond. Instead of “ideal cut,” sapphires with a good quality cut is one that accentuates even medium color tones, reduces the prominence of inclusions, increases reflection, and therefore refraction of incident light (avoidance of “windows”), and showcases the maximum carat weight of the stone when set in jewelry. Commonly found shapes for sapphires are ovals and cushions.
4. When choosing based on clarity, one must put into account that almost all non-synthetic blue sapphire gemstones have internal inclusions. Finding one without inclusions is extremely rare and highly valuable. Almost all blue sapphires have been heat-treated to enhance its color, so heat-treating is a common enhancement among sapphires as well as other colored gemstones.
5. When choosing a sapphire based on carat weight, one must consider that sapphires have higher density than diamonds. A one carat diamond would look larger than a one carat sapphire.