Garnet Buying Guide
With so many colors and varieties available, garnet buying can be daunting. Whether starting your collection or completing it, our guide can help.…
Proteus Information
| Data | Value |
|---|---|
| Name | Proteus |
| Is a Variety of | Garnet |
| Colors | Dark red with metallic, dark gray luster in reflected light. |
| Fracture | Conchoidal |
| Hardness | 6.5-7.5 |
| Cleavage | None |
| Crystallography | Isometric. |
| Birefringence | None. |
| Dispersion | 0.022-0.027 |
| Luminescence | None. |
| Luminescence Present | No |
| Absorption Spectrum | Almandines have a distinctive, diagnostic absorption spectrum: A band 200 Å wide at 5760 (strong) and also strong bands at 5260 and 5050. Lines may appear at 6170 and 4260. In pyrope, the chromium spectrum of emission lines in the far red is absent. However, the almandine (iron) spectrum is often visible. Otherwise, Cr masks the almandine spectrum and we see a narrow, weak doublet at 6870/685O, with possible weak lines at 6710 and 6500. A broad band, about 1000 Å wide, may be visible at 5700. |
| Pleochroism | None. |
| Optics | Isotropic. |
| Luster | Metallic. |
| Specific Gravity | 3.65-4.30 |
| Enhancements | Heating produces a metallic crust. |
| Typical Treatments | Heat Treatment |
| Transparency | Transparent to translucent. |
| Birthstone | January |
In Greek mythology, Proteus was a sea god, capable of changing his shape. It has become a noun for one who easily changes their appearance or principles.
Proteus are the only treated garnets. All the others resist change, but a few almandine/pyropes from the US will change into Proteus. The treatment brings a thin layer of metals to the surface.
This causes it to have a dual appearance. In reflected light, they have a dark gray, metallic luster, much like hematite. In transmitted light, the dark red of the garnet shows through.
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