Gemstone Windows and Dark Patches: What to Look for in a Cut Gem

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AI-generated educational illustration. Conceptual only; not a photograph of an actual specimen or location. A coloured gem may have a pale, see-through centre or areas that look almost black. Both affect its appearance, but they do not have the same cause. What is a window? A window is an area where light passes through the gem instead of being returned towards the viewer. You may see the background through it, especially near the centre. Cutting angles and the material's refractive index—how it bends light—help determine whether this happens. There is no single ideal depth for every gemstone. Why dark patches need a closer look Darkness can have several causes. The material may absorb a lot of light. Some facets may reflect dark surroundings or the observer. Extinction is another cause, involving light that is not returned to the viewer after internal reflection. For that reason, calling every black patch “extinction” can be misleading. A simple viewing routine Look at the gem fac...
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New Ethiopian Copper-Bearing Tourmaline: What Gem Collectors Should Know

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A newly reported source of copper-bearing tourmaline from Ethiopia is drawing attention across the gem trade. The news matters because copper-bearing tourmalines can show exceptional blue-green colour, and a new source can create excitement, confusion, and misinformation at the same time. What has been confirmed? GIA and Gübelin Gem Lab report that they examined samples attributed to a new Ethiopian deposit and identified them as copper-bearing tourmaline. Their research describes independent laboratory work on the material; fuller technical studies are expected in their gemological publications. Why the story is important Copper-bearing tourmaline is a major subject for collectors because colour, origin, treatment, cutting and laboratory documentation can all influence how a stone is described and valued. A vivid blue-green appearance alone does not establish a geographic origin or a trade name. Three smart questions before buying 1. Is there an independent laboratory report? A report helps establish what the stone is and whether an origin opinion is offered. 2. Is treatment disclosed? Ask the seller for clear treatment information in writing. Do not assume that an attractive colour is untreated. 3. Are photographs accurate? Tourmaline can look very different under daylight, LED light and studio lighting. Request videos and ask to see the stone in more than one lighting condition. A gemologist’s caution This discovery is exciting, but it is too early to treat every blue-green tourmaline offered online as material from the new Ethiopian source. Identification and origin work require gemological testing, and a laboratory report is more reliable than a social-media claim or a photo. Quick takeaway New material can be fascinating for collectors, but good buying decisions still depend on disclosure, documentation and independent testing—not just colour or a trending name. Sources GIA and Gübelin Gem Lab: https://www.gia.edu/gia-news-press/gia-and-gubelin-gem-lab-confirm-new-source-of-copper-bearing-tourmaline-from-ethiopia GIA Gem News, Tucson 2026 overview: https://www.gia.edu/gems-gemology/spring-2026-gemnews-tucson-overview Have you seen Ethiopian copper-bearing tourmaline offered for sale? Share the report details and images you would want to verify before buying.

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