How do I identify Milanriederite?

Milanriederite can be identified by its hardness of 6 on the Mohs scale, dark brownish-red color. Look for these key characteristics when examining specimens.

What color is Milanriederite?

Milanriederite typically appears in dark brownish-red. Color can vary depending on impurities and formation conditions.

How hard is Milanriederite?

Milanriederite has a hardness of 6 on the Mohs scale. This gives it moderate hardness.

Milanriederite

A variety of Minerals

What is Milanriederite?

Milanriederite Market Value Calculator

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Milanriederite Localities Map

See where Milanriederite 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

Quick Facts

Physical Properties

Color: dark brownish-red
Hardness (Mohs): 6
Density: 3.547 g/cm³

Chemical Properties

Chemical Formula: (Ca18[REE])Fe3+Al4(Mg4Al4)(☐4)☐[Si2O7]4(SiO4)10(OH)9 According to Mössbauer data, all iron in the mineral is trivalent. The formula is a partial simplification of the full structural formula. The large (VII-IX)-coordinated (X4)2(X3)8(X2)8(X1) sites are here combined (e.g. Ca19) and are typically filled with Ca, although other large cations such as the REE may be present. The square-pyramidal Y1 site can host a variety of M2+ and M3+ ions and is the basis for the distinction of several species. The VI-coordinated Y2 site typically is filled with Al, whereas the also VI-coordinated Y3 site may contain Al, Mg, and other cations of similar charge and size. The tetrahedral T1 site is typically vacant but may contain B (less commonly Al); the trigonal T2 site is also typically vacant but may also contain B. Some of the (SiO4) may be replaced by (H4O4), akin to the Si4+ ↔︎ 4H+ hydrogarnet substitution. Among the oxygen that are not part of the silica tetrahedra, there are eight "O11" that typically occur as OH, two "O10" that are typically O & OH or OH & OH (the latter arrangement notably when Y1 is an M2+ cation). There may also be up to three "O12" that in most vesuvianite-group minerals are absent (and are not included here), but may be present particularly when T1 is occupied. Note: The published formula by Chukanov et al., 2019 includes ∑(REE+Y) = 1.97 apfu (primarily in the X3 site), although this amount does not dominate the site and so might be disregarded when considering the end-member formula. However, the extra charge afforded by this REE inclusion appears necessary to provide charge balance for defining M2+>M3+ in the Y3 site, as full hydrogenation of the "O10" and "O11" positions would be otherwise insufficient. Indeed, the IMA formula includes more H than is permissible by the formula, and is also inconsistent with what Chukanov et al., 2019 report (9.96 apfu OH). To address this inconsistency and to closer approximate the published analysis, one apfu of REE is included in the presented formula to maintain charge balance (although other charge-balancing mechanisms, such as the addition of B into the normally vacant T1 and/or T2 sites, may also be possible).
Elements: Al, Ca, Fe, H, Mg, O, Si

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