blem·ish | ˈble-mish
A flaw, spot, or scratch on the surface of a gemstone
In jewelry terms, a blemish refers to a flaw, spot, or scratch on the surface of a gemstone. You may be most familiar with the term blemish referring to these flaws on a diamond. When it comes to purchasing a diamond, blemishes affect the stone’s clarity. Blemishes occur on diamonds after the stone’s formation. Blemishes most commonly happen when the diamond is being cut, set, or as a polished diamond is being worn. While blemishes can impact the brilliance of a diamond and impact the diamond’s value, some of them are too small to be seen by the naked eye. Among the most common examples of blemishes on any gemstone type - diamond or otherwise - include nicks, scratches, chips, and abrasions that occur during the handling, mounting, or wearing of the gemstone. Additional types of blemishes that may occur during the manufacturing process of the piece of jewelry include extra facets, polish lines, and burns, which are a result of the excessive heat that is emitted by the polishing wheel when the gemstone is being cut.