Proteus Value, Price, and Jewelry Information

Home » Gemstones » Proteus Value, Price, and Jewelry Information

Proteus

Proteus Information

Data	Value
Name	Proteus
Is a Variety of	Garnet
Colors	Dark red with metallic, dark gray luster in reflected light.
Crystallography	Isometric.
Luster	Metallic.
Hardness	6.5-7.5
Fracture	Conchoidal
Specific Gravity	3.65-4.30
Birefringence	None.
Cleavage	None
Dispersion	0.022-0.027
Luminescence	None.
Luminescence Present	No
Enhancements	Heating produces a metallic crust.
Typical Treatments	Heat Treatment
Transparency	Transparent to translucent.
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.
Birthstone	January
Pleochroism	None.
Optics	Isotropic.

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.

by International Gem Society