Diamonds Under the Scope
April 11, 2016
Another world exists in gemstones when they are viewed through a microscope. Landscapes and whimsical creatures appear to come to life as you explore a gem’s internal features and formations.
Inclusions spin a tale of provenance and tell of the diamond's journey from deep within the earth to the surface. They are a geological time capsule that tells the story of a gem’s formation. Feather inclusions in a diamond, for example, can be indicative of a rough ride from the earth’s mantle to the surface. These birthmarks are signs of a diamond’s natural origin and make your diamond unique in the world.
In 1645 an Englishman saw a red crystal inclusion (probably a garnet) in a diamond belonging to a Venetian nobleman by the name of Rugini. This discovery sparked an interest in coloured crystal “guest” minerals or inclusions in diamond. A number of crystal mineral inclusions have been reported since then.
Inclusions impart character, beauty and essence to their host gems.
The renowned Swiss gemmologist Dr Edward J. Gübelin (1913-2005) built a legacy on the study and systematic classification of the internal world of gemstones. His research demonstrated the importance of these internal features in determining a gem’s identity.
John I. Koivula, GIA’s analytical microscopist and long-standing chief research gemmologist, wrote to Dr Gübelin as a teenager, sending along his first photomicrographs (photos taken through a microscope). This began a collaboration that would culminate in the three-volume "Photoatlas of Inclusions in Gemstones" landmark works that established the importance of inclusions as an aid to identifying gemstones. Their photomicrographs of inclusions illustrate common features in gemstones from particular localities. Their richly illustrated tomes also help separate natural from synthetic or treated gemstones, including diamonds.
Diamonds present some of the most striking inclusions to view under the microscope and host a variety of gemstone guest crystals. Some of the most frequently found are pyrope garnet, olivine or peridot, diopside, chrome-spinel, and much less frequently, ruby and sapphire. Diamond crystals are also frequently seen as inclusions within diamond itself.
The study and documentation of inclusions in diamond has inspired poetic and descriptive names: feather, cloud, halo, knot, needle, bearding and pinpoint. With magnification, these scenes offer clues to the natural origin of a diamond and give you a renewed appreciation for its characteristics and qualities. The possibilities of what you can see in these photomicrographs is almost endless.
Sharon Bohannon, a media editor who researches, catalogues and documents photos, is a GIA GG and GIA AJP. She works in the Richard T. Liddicoat Gemological Library and Information Center.