Peach eosphorite, 13.14-ct, 20.2 x 15.5 x 8.5 mm, fancy shield cut, Brazil. © ARK Rare Gems. Used with permission.
Faceted eosphorites in pale colors are quite attractive and easy to cut. However, these very rare gems are too soft for most jewelry use.
| Data | Value |
|---|---|
| Name | Eosphorite |
| Formula | (Mn,Fe)AlPO4(OH)2·H2O. |
| Etymology | From the Greek eosphoros for “dawn bearing,” alluding to the rosy pink color of the original source material. |
| Occurrence | In granite pegmatites, usually associated with Mn phosphates. |
| Inclusions | Almost always included; multiphase (liquid). |
| Colors | Colorless, pale pink, pale yellow, light to dark brown, reddish brown, orange, black. |
| Fracture | Uneven to subconchoidal |
| Hardness | 5 |
| Cleavage | Poor |
| Crystallography | Orthorhombic. (Previously classified as monoclinic with pseudo-orthorhombic symmetry. See “Comments” below). |
| Refractive Index | 1.638-1.671 |
| Birefringence | 0.029-0.032. (Note: less than Childrenite) |
| Luminescence | None observed |
| Luminescence Present | No |
| Absorption Spectrum | Strong line at 4100, moderate at 4900 (in brownish-pink material). |
| Pleochroism | Distinct: yellow/pink/pale pink to colorless. |
| Optics | a = 1.638-1.639; β = 1.660-1.664; γ = 1.667-1.671. Biaxial (-), 2V= 50°. |
| Luster | Vitreous to resinous |
| Specific Gravity | 3.05 (pure Mn end member); 3.08 (Brazil). |
| Transparency | Translucent to transparent |
| Optic Sign | Biaxial - |
Cut eosphorites, Brazil. Gem cutting by Afonso Marques. Photo by Eurico Zimbres. Licensed under CC By-SA 3.0.
The minerals eosphorite and childrenite form a series, with eosphorites as the manganese (Mn)-dominant member and childrenites as the iron (Fe)-dominant. Varying combinations of Fe and Mn amounts in crystals give eosphorites a wide range of colors, and those with high levels of Mn may show an orange color. However, most eosphorites are usually brown and turn brown to black when oxidized.
The pink colors that inspired eosphorite’s name look especially beautiful when cut as round brilliants.
Originally, scientists grouped eosphorites in the monoclinic crystal system because their apparent pseudo-orthorhombic symmetry was ascribed to twinning. However, subsequent studies determined eosphorites definitively belong to the orthorhombic crystal system.
Eosphorite crystals, Taquaral, Itinga, Jequitinhonha valley, Minas Gerais, Brazil, 2.4 x 2.6 cm. Photo by Modris Baum. Public Domain.
Although both are very rare, cut eosphorites are more commonly encountered than childrenites. Childrenites tend to have more yellow color, but can also show brownish colors like eosphorites. These fellow series members differ somewhat in specific gravity, birefringence, and optical properties.
Apatite colors and hardness may match those of eosphorite. However, these stones appear more frequently as faceted collector’s pieces and differ optically considerably from much scarcer eosphorites.
Eosphorite and rose quartz crystals, Ilha claim, Taquaral, Itinga, Jequitinhonha Valley, Minas Gerais, Brazil. Photo by Géry Parent. Licensed under CC By-ND 2.0.
No known synthetics or gem treatments.
To date, only Brazilian localities have yielded cuttable crystals. Itinga, Minas Gerais produces excellent, flat, pink crystals up to 4 x 1 cm.
Other notable crystal sources include the following:
Closeup of a bright orange euhedral eosphorite crystal on a white albite (cleavelandite) matrix. This specimen also features smoky colored topaz and pinkish purple lepidolite. Chamachhu, Haramosh Mts., Skardu District, Baltistan, Northern Areas, Pakistan. 7.3 x 4.7 x 2.8 cm. © Rob Lavinsky, www.iRocks.com. Used with permission.
Always small in size, cut eosphorites typically weigh less than 3-4 carats. Cuttable crystals are usually badly flawed and contain many inclusions.
Brilliant cushion-cut eosphorite, 10.54 cts, 11.9 mm, Brazil. © The Gem Trader. Used with permission.
You’re more likely to find faceted eosphorites, if at all, in gem collections than jewelry collections. Since these gems are soluble in acid, don’t expose them to any cleaning solutions that contain acids or wear them against your skin.
With a hardness of 5, these gems have greater susceptibility to scratching than many more commonly encountered jewelry stones, so use protective settings in jewelry. Store eosphorites separately from other gems to avoid contact scratches as well. Clean these gems with a soft brush, mild detergent, and warm water, but don’t soak them in water. See our Gemstone Jewelry Cleaning Guide for more recommendations.
Although this pear-cut eosphorite has eye-visible inclusions, it has a beautiful peachy orange color. Taquaral, Minas Gerais, Brazil, 9.26 mm x 6.40 mm, 1.51 cts. © Rob Lavinsky, www.iRocks.com. Used with permission. (Images combined to show details).
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