Pyroxmangite Mineral Overview

• Mineral name: Pyroxmangite
• Mineral class: Silicate (inosilicate, pyroxenoid group)
• Chemical formula: MnSiO₃
• Crystal system: Triclinic
• Mohs hardness: 5.5–6
• Color range: Pink, reddish-pink, brownish-red, grayish
• Luster: Vitreous
• Streak: White
• Cleavage: Perfect in one direction, good in another
• Fracture: Uneven to splintery
• Specific gravity: Approximately 3.5–3.7
• Transparency: Translucent to opaque
• Common locations: Japan, United States, Sweden, South Africa
• Uses: Collector mineral, ornamental stone
• Similar minerals: Rhodonite, spessartine, tephroite

Naming and Classification

Pyroxmangite is a manganese silicate mineral and a member of the pyroxenoid group, closely related to rhodonite.

Its name reflects both its composition and structure:

• “Pyrox-” → similarity to pyroxenes
• “-mangite” → manganese content

Although it shares the same chemical formula as rhodonite (MnSiO₃), it differs in crystal structure, making it a distinct mineral species.

Physical and Optical Characteristics

Pyroxmangite typically occurs as:

• Massive or granular material
• Rarely as small prismatic crystals

It is usually pink to reddish, though often darker or more subdued than rhodonite, sometimes appearing:

• Brownish-red
• Grayish-pink

The luster is vitreous, giving fresh surfaces a glassy appearance. With a hardness of 5.5 to 6, it is moderately hard.

It shows good to perfect cleavage, and fracture is uneven or splintery.

Relationship to Rhodonite

Pyroxmangite is often confused with rhodonite due to:

• Identical chemical formula (MnSiO₃)
• Similar pink coloration

Key differences:

• Pyroxmangite: Triclinic structure, typically more subdued color
• Rhodonite: Triclinic but structurally different arrangement, often brighter pink with black veining

Pyroxmangite usually lacks the distinct black manganese oxide veining seen in rhodonite.

Chemical Composition and Structure

Pyroxmangite is composed of:

• Manganese (Mn)
• Silicon (SiO₃ chains)

It features chain silicate structures, but unlike true pyroxenes, the chains are slightly distorted, placing it in the pyroxenoid category.

Formation and Geological Occurrence

Pyroxmangite forms in manganese-rich environments, particularly in:

Metamorphic Rocks

• High-pressure, moderate-temperature conditions
• Metamorphosed manganese deposits

Hydrothermal Systems

• Deposited from manganese-rich fluids

It is commonly associated with:

• Rhodonite
• Spessartine garnet
• Quartz
• Other manganese minerals

These associations reflect specialized manganese-rich geological settings.

Common Locations

Notable occurrences include:

• Japan: Classic locality and early studies
• United States: California and Colorado
• Sweden: European deposits
• South Africa: Manganese-rich regions

Japanese material is especially important historically.

Uses and Practical Significance

Pyroxmangite has limited practical use:

• Collector mineral: Especially for those specializing in manganese minerals
• Ornamental stone: Occasionally polished

It is not a major ore mineral.

Similar and Related Minerals

Pyroxmangite can resemble:

• Rhodonite: Brighter pink, often with black veining
• Spessartine garnet: More orange and crystalline
• Tephroite: Typically less pink and more granular

Distinguishing pyroxmangite often requires:

• Structural analysis
• Careful observation of color and texture
• Geological context

Identification Notes for Collectors

• Look for pink to reddish material without strong black veining
• Note moderate hardness (5.5–6)
• Observe vitreous luster
• Check cleavage and splintery fracture
• Consider association with manganese-rich rocks

Pyroxmangite is a manganese silicate mineral, recognized for its relationship to rhodonite and occurrence in manganese-rich metamorphic environments, making it an important species for collectors and mineralogists studying manganese systems.