GIA GEMOLOGIST ARTICLE

Why Are Some Gemstones Cut As A Cabochon?

What is a cabochon, what makes it different from a faceted gemstone and why are they cut this way? Read on to find out.

Nicky Thomas

Gemstone & Jewelry
Style & Trends Editor


  • Cabochon Vs Faceted

  • A Cabochon (or cutting en cabochon – French: “in the manner of a cabochon”) is a type of cut used on gemstones where by the stone is shaped and polished into a smooth, generally convex shape with a flat base. Cabochons or Cabs are generally circular or oval but may be cut into different shapes.

     Cabochon Cutting.jpg

    Cabochon Polishing at our Gem Cutting Center

    Cabs are usually used on softer species, such as Opal or Moonstone (Mohs Scale of Hardness), opaque gems or gems of a lower grade. Gem cutting is a fine art and is done to enhance the gems natural qualities and transform it into a piece that best displays these attributes. Cabochons often act like a window, allowing one to see the gems natural details inside and display other visual effects such as play of color in Opals, cat’s eye and asterism (star). Cabochons are more likely to have natural inclusions and markings.

    Play of color cats eye star.jpg

    Cabochon cutting dates back to the Middle Ages and has remained a popular cut ever since.

    Cab Vs Faceted image.jpg

    FACETING
    is another form of cutting a gemstone. An ancient art where by a gem is methodically cut with numerous flat surfaces using the appropriate or critical angles of the gems structure on the top and bottom of the stone, this is to allow light to refract and reflect through the gem to enhance its brilliance and give the stone its sparkle. The more facets a stone has, the more “lively” a gem will be.  Faceted gems have polished flat faces (the table) and pointed bottoms (the pavilion). For further information on gem cutting please see our Gemstone Cutting Article.

    Faceted cuts are generally used on harder gemstones that are transparent or “clean” and for fine gems as any inclusion or markings would disturb the light passing through the stone and therefore decrease its beauty.

    Tourmaline Colors lr.jpg

    Faceted Tourmalines 

    Faceted stones are available in many forms, the four most common being Brilliant Cut, Step Cut, Drop Cut and Mixed Cut. Different shapes are cut using these different forms.

    It was only until the 15th Century that faceting gemstones was possible, as the abrasive properties of Diamonds was discovered and used.  Master Cutters use Diamond powder on cutting machines and proper knowledge of the crystals structure to ensure top cutting. This is done at a sacrifice, as often up to 30% of the stone is lost, however the value of the gem is greatly improved as a result.

      Gem cutting and polishing.jpg
    Gemstone faceting at our Gem Cutting Center

    At The Rare Gemstone Company we have been cutting colored gemstones since we started in 1974. Our first Master Cutter was taught by a German Master Cutter and since then we have been teaching and training up new cutters in this fascinating ancient art.


ABOUT THE AUTHOR Nicky Thomas

Educated at the University of Exeter and a key part of our team here at The Rare Gemstone Company, Nicky has been fascinated by gemstones and jewelry since childhood. She explores all areas of the industry in her blog and revels in the proximity to gems and jewels that working at the source of some of the world’s most beautiful and rarest gemstones provides her.

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