How do I identify Magnesio-riebeckite?

Magnesio-riebeckite can be identified by its hardness of 5 - 5.5 on the Mohs scale, Light blue to blue-black. color. Look for these key characteristics when examining specimens.

What color is Magnesio-riebeckite?

Magnesio-riebeckite typically appears in Light blue to blue-black.. Color can vary depending on impurities and formation conditions.

How hard is Magnesio-riebeckite?

Magnesio-riebeckite has a hardness of 5 - 5.5 on the Mohs scale. This gives it moderate hardness.

Magnesio-riebeckite

A variety of Minerals

What is Magnesio-riebeckite?

Riebeckite is a sodium-rich member of the amphibole group of silicate minerals, chemical formula Na2(Fe3Fe2)Si8O22(OH)2. It forms a solid solution series with magnesioriebeckite. It crystallizes in the monoclinic system, usually as long prismatic crystals showing a diamond-shaped cross section, but also in fibrous, bladed, acicular, columnar, and radiating forms. Its Mohs hardness is 5.0–6.0, and its specific gravity is 3.0–3.4. Cleavage is perfect, two directions in the shape of a diamond; fracture is uneven, splintery. It is often translucent to nearly opaque.

Magnesio-riebeckite Market Value Calculator

Estimate the market value of Magnesio-riebeckite using size, quality, and finish. This preview calculator is for quick context and is not a formal appraisal.

Magnesio-riebeckite Localities Map

See where Magnesio-riebeckite is found with a localities map, collecting zones, and geology context. Generate a sample map preview below.

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North ZoneCentral RidgeSouth Basin

Key Characteristics

Formation of Magnesio-riebeckite

It typically forms dark-blue elongated to fibrous crystals in highly alkali granites, syenites, rarely in felsic volcanics, granite pegmatites and schist. It occurs in banded iron formations as the asbestiform variety crocidolite (blue asbestos). It occurs in association with aegirine, nepheline, albite, arfvedsonite in igneous rocks; with tremolite, ferro-actinolite in metamorphic rocks; and with grunerite, magnetite, hematite, stilpnomelane, ankerite, siderite, calcite, chalcedonic quartz in iron formations.

Quick Facts

Physical Properties

Color: Light blue to blue-black.
Hardness (Mohs): 5 - 5.5
Streak: Pale grey to bluish-grey.

Chemical Properties

Chemical Formula: ◻{Na2}{Mg3Fe3+2}(Si8O22)(OH)2 Magnesio-riebeckite is defined as a member of the riebeckite group with Mg>Fe2+ in the C2+ position and (OH) in the W position.
Elements: Fe, H, Mg, Na, O, Si