Does Vivianite Make a Good Jewelry Stone? In an interview, rare-gem faceter and supplier C. D. Parsons acknowledges looking forward to cutting vivianite someday, something very few have done. With a hardness between talc and gypsum (1.5-2) and perfect cleavage, few could manage this feat. Thin pieces are even flexible and sectile (cuttable with a knife). Due to their fragility, vivianites would not make good jewelry stones. However, this gem material can show beautiful dark shades of blue and green. It also displays intense pleochroism. Depending on the viewing angle, stones can reveal up to three colors, including yellowish green and olive-green, blue-green, and indigo. When mined, vivianites are colorless or pale green, but their colors darken after exposure to light. As a result, an enthusiast may find an attractive color disappearing over time. Not surprisingly, this further de-incentivizes cutting an already challenging stone. Still, the appeal remains. You’re more likely to find vivianites in mineral collections than jewelry collections. vivianite – Huanuni Mine Vivianite crystal, Huanuni Mine, Huanuni, Dalence Province, Oruro Department, Bolivia. Photo by Géry Parent. Licensed under CC By-SA 3.0. Is There Vivianite in Odontolite? In the past, vivianite was believed to be the cause of the blue color of so-called odontolite. This fossilized bone and teeth material may resemble turquoise. (It’s also called “bone turquoise”). However, heat treatments have been shown to produce the color artificially. Identifying Vivianite Like its coloration, vivianite’s streak starts colorless but becomes dark blue over time. Please note: don’t conduct streak testing on finished gems. Test material in inconspicuous spots as a last resort only. Bolivian material has the following properties. Refractive indices (RI): 1.585, 1.603, and 1.639. Specific gravity (SG): 2.64. Are There Synthetic Vivianites? Scientists have synthesized vivianite for a variety of purposes, including environmental and agricultural research. However, there’s no known jewelry use for this lab-created material. There are no known gemstone treatments or enhancements. Where are Vivianites Found? The following sources yield good-quality gem material: Bolivia, Llallagua and Poopo: fine, cuttable crystals to 6 inches long. Cameroon, N’gaoundere: massive crystals up to 4 feet long, dark in color, cuttable. United States: Lemhi County, Idaho, fine crystals; Richmond, Virginia, good crystals; Bingham Canyon, Utah, crystals to 5 inches in length. Other notable sources include the following: United States: California; Colorado; Delaware; Florida; Maryland; New Jersey; Black Hills, South Dakota (in pegmatites). Australia; Canada; England; France; Germany; Japan; Russia. vivianite – Germany An unusual specimen of radiating, intergrown blade-shaped vivianites. Hesse, Germany. © Rob Lavinsky, www.iRocks.com. Used with permission. Stone Sizes Gem cutters rarely facet vivianites, and their almost micaceous cleavage makes polishing gems very difficult. For example, the Bolivian material could yield cut stones up to 75-100 carats. However, this just doesn’t occur. Caring for Vivianites Store your vivianite specimens out of the light to protect their color. Consult our gemstone jewelry cleaning guide for more recommendations.