How to identify Rhodonite

To correctly identify Rhodonite (MnSiO3), check each of these features in order. Many rocks and minerals look alike, so cross-reference multiple properties before deciding.

Step-by-step identification

1. 1

   Color

   Overall color and any zoning or banding

   Pink to rose-red, reddish-brown, sometimes yellowish-brown. Often has black manganese oxide veins or dendrites.

2. 2

   Luster

   How the surface reflects light: metallic, vitreous, dull

   Vitreous (glassy) to pearly on cleavage surfaces.

3. 3

   Texture

   Grain size and surface feel: coarse, fine, glassy

   Typically massive, granular, or compact. Crystals are rare, usually tabular.

4. 4

   Crystal Form

   Shape of visible crystals or crystal faces

   Triclinic system. Crystals are typically tabular, often with rounded edges. More commonly found as massive aggregates.

5. 5

   Cleavage

   How it breaks: flat cleavage planes vs irregular fracture

   Perfect cleavage in two directions at nearly 90 degrees (87°40').

6. 6

   Geological Environment

   The rock formation and setting where it occurs

   Manganese-rich metamorphic rocks, metasomatic deposits, contact metamorphic zones, and occasionally in some igneous rocks.

Key Facts

Hardness

5.5-6.5 (Mohs scale)

Specific Gravity

3.4-3.7

Crystal System

Triclinic

Color

Pink, rose-red, reddish-brown, sometimes yellowish-brown

Luster

Vitreous to pearly

Transparency

Translucent to opaque, rarely transparent

Fracture

Uneven to conchoidal

Cleavage

Perfect in two directions at nearly 90 degrees (87°40')

Composition

Manganese silicate (MnSiO3), often with minor substitution of Ca, Fe, and Mg for Mn.

Physical characteristics

• Crystal Habit: Typically massive, granular, or compact. Crystals are rare, usually tabular with rounded edges.
• Cleavage Type: Perfect {110} and {1-10} at 87°40'
• Fracture Type: Uneven to conchoidal
• Tenacity: Brittle
• Luster Type: Vitreous to pearly

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