Pyroxmangite Value, Price, and Jewelry Information
Pyroxmangite grains are rare, seldom clean enough to facet, and difficult to cut. However, when cut, they are extremely beautiful and rich in color.
Pyroxmangite Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Pyroxmangite Information
| Data | Value |
| Name | Pyroxmangite |
| Crystallography | Triclinic, Crystals tabular; usually massive, in grains, cleavable. |
| Refractive Index | 1.726-1.764 |
| Colors | Reddish brown, dark brown, pale to rose pink, purplish pink. The darker colors are due to alteration. |
| Luster | Vitreous to pearly. |
| Fracture | Uneven |
| Hardness | 5.5-6 |
| Specific Gravity | 3.61-3.80 |
| Birefringence | 0.016-0.020 |
| Cleavage | Perfect 2 directions |
| Dispersion | 0.015 (C-F) |
| Luminescence | None. |
| Transparency | Transparent to translucent. |
| Absorption Spectrum | Not diagnostic. |
| Formula | (Mn,Fe)SiO3. |
| Pleochroism | Slight in shades of pink and red. |
| Optics | a = 1.726-1.748; β = 1.728-1.750; γ = 1.744-1.764. Biaxial (+), 2V = 35-46°. |
| Etymology | Originally thought to be manganiferous pyroxene. |
| Occurrence | In metamorphosed rocks rich in manganese. |
Comments
Although pyroxmangites can show stunning transparent red colors, from reddish brown to purplish pink, these rare gems have perfect cleavage in two directions. This makes them difficult for faceters to cut and means they have great susceptibility to fracture from blows, thus, you’ll rarely see them used as jewelry stones.
Pyroxmangite forms a series with pyroxferroite. In pyroxferroites, the iron (Fe) content exceeds the manganese (Mn) content. (The pyroxmangite type material from South Carolina later proved to be pyroxferroite).
Pyroxmangites are also polymorphous with the popular gem material known as rhodonite, sharing the same chemical structure. Sometimes, they occur together.
Identifying Characteristics
Even professional gem labs may have difficulty distinguishing pyroxmangites from rhodonites. Although rhodonites may have slightly lower refractive index (RI), birefringence, and specific gravity (SG) values, these properties as well as their colors, pleochroism, optic character, and hardness may largely overlap. Sometimes, a powder X-ray diffraction (XRD) analysis may be needed.
Synthetics
Scientists have synthesized pyroxmangite to study its polymorphism with rhodonite. However, there is no known jewelry use for this synthetic material.
Enhancements
None known.
Sources
Honshu, Japan and Brazil have produced gemmy material. Other notable sources include the following:
- United States: Kern County, California; Colorado; Boise, Idaho (pale pink material).
- Australia: Broken Hill, New South Wales (in fine crystals and grains, with rhodonite).
- Finland (brown); Peru; Spain; Sweden (red-brown); Scotland, United Kingdom.
Stone Sizes
Any faceted pyroxmangites are always small, since the material is extremely scarce and available only as small transparent grains, but faceters can cut large cabochons from cleavages and massive materials. Collectors should expect to see stones up to about 2 carats.
Care
Due to their cleavage, don’t clean pyroxmangites with mechanical systems such as ultrasonic or steam. Clean these gems only with a warm damp cloth, mild detergent, and soft brush. For more care recommendations, consult our gemstone jewelry cleaning guide.
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