Romanèchite
(Ba,H2O)2(Mn4+,Mn3+)5O10IMA symbol: Rmnapproved
Romanèchite is an oxide or hydroxide mineral with the formula (Ba,H2O)2(Mn4+,Mn3+)5O10, crystallizing in the monoclinic system. It has a Mohs hardness of 5-6, typically black or gray in color, with a dull or metallic luster, a specific gravity of 3.7-4.7. Its streak is black or brown.
Photos
Crystallography
| Crystal system | monoclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | C 1 2/m 1 |
| Cell (Å, °) | a = 13.929, b = 2.8459, c = 9.678; α = 90, β = 92.39, γ = 90 |
| Cell volume | 383.307 ų, Z = 2 |
| Axial ratios | 4.8944:1:3.4007calculated from COD 9001175 |
| Source structure | COD 9001175 (American Mineralogist, 1988) |
Powder X-ray diffraction (calculated)
| d (Å) | 2.187 | 2.407 | 2.879 | 3.479 | 1.821 | 3.318 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 80.4 | 74.8 | 74.4 | 73.4 | 72.8 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9001175; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 4.715 g/cm³calculated from COD 9001175 |
|---|---|
| Hardness (Mohs) | 5-6single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.7-4.7 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, graysingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | black, brownsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | dull, metallic, submetallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 4.DK.10Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 4.DK.10Wikidata (CC0) |