How do I identify Hubeite?

Hubeite can be identified by its hardness of 5.5 on the Mohs scale, Dark brown to light brown in thinner crystals. color. Look for these key characteristics when examining specimens.

What color is Hubeite?

Hubeite typically appears in Dark brown to light brown in thinner crystals.. Color can vary depending on impurities and formation conditions.

Hubeite has a hardness of 5.5 on the Mohs scale. This gives it moderate hardness.

Hubeite

A variety of Minerals

What is Hubeite?

The mineral hubeite, Ca2MnFe[Si4O12(OH)]·(H2O)2, is a sorosilicate of the Si4O13 group. Structurally it also belongs to the Akatoreite group. It was found and named after the province of Hubei, China. It is common to iron ores in a mine of that region. It occurs mainly as aggregates of fan like crystals. It is dark to pale brown, has orange-brown streak and is vitreous. Hubeite has a hardness of 5.5 in the Mohs scale, one good cleavage and conchoidal fracture. It is triclinic with a space group of P1*. The structure of hubeite is very uncommon, and in fact there is only one other mineral that fits the Si4O13 group, which is ruizite.

Hubeite Market Value Calculator

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Hubeite Localities Map

See where Hubeite 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

Characteristics of Hubeite

Hubeite is most common as aggregates of intergrown crystals (Fig.1) that are usually less than 5 mm across and that have individual crystals with well-developed faces that are as long as 1 mm (Hawthorne et al., 2002). The color ranges from pale to dark brown, depending on the crystal size (Fig.2). Other properties consist of a pale orange-brown streak, vitreous luster, non-fluorescence, and one good cleavage parallel to the c-axis. It is also brittle with conchoidal fracture, has a hardness of 5.5 in the Mohs scale and a specific gravity of 3.02 (Hawthorn et al., 2002). As for optical features, it is important to note that hubeite is strongly pleochroic, biaxial with an indeterminate optic sign and has a birefringence of 0.023 (γ-α) (Hawthorne et al., 2002).

Formation of Hubeite

Hubeite is mainly associated to a skarn assemblage with pink inesite, colorless apophyllite, quartz, pyrite and colorless-white calcite (Hawthorne et al., 2004). They all occur together at the Daye Mine. Usually hubeite appears in two different situations. It may occur as isolated aggregates of crystals perched on white quartz, or it may occur covering both sides of thick specimens, that are usually pink inesite and apophyllite (Hawthorne et al., 2002). Figures 3 and 4 illustrate both situations. The localities where ruizite is found, associated with apophyllite, inesite and pyrite as well, and there is no hubeite, which leads the conclusion that hubeite needs oxidized environments and sufficient concentration of iron to occur. The Daye mine is an iron ore deposit (Dingyu et al., 1982). This specific area is characterized by deposits of late Paleozoic carbonate rocks in contact with plutons aging between the middle Jurassic to middle Cretaceous (Dingyu et al., 1982). According to Dingyu et al. (1982), the iron rich magma injections are the main cause for the formation of the ore deposits of the region. These polymetallic deposits form a belt that crosses China in the west–east direction (Ottens, 2007). Curiously, the mine where hubeite was first found is in fact a wollastonite source for minerals collectors.

Composition of Hubeite

To analyze the composition, an electron microprobe was used in the wavelength-dispersion mode (Hawthorn et al., 2002). The quantity of (OH) and (H2O) was acquired by solid solution and refinement, based on previous work by Hawthorne et al., 1990. To assure the presence of (OH) and (H2O) groups, an infrared spectrum was also recorded (Hawthorn et al., 2002).