Rhodonite
CaMn3Mn(Si5O15)IMA symbol: Rdnredefined
Rhodonite is a silicate mineral with the formula CaMn3Mn(Si5O15), crystallizing in the triclinic system. It has a Mohs hardness of 5.5-6.5, typically black, brown, green or pink in color, with a pearly or vitreous luster, a specific gravity of 3.4-3.68. Its streak is white.
Photos
Crystallography
| Crystal system | triclinic crystal systemWikidata (CC0) |
|---|---|
| Space group | P -1 |
| Cell (Å, °) | a = 6.6818, b = 7.633, c = 11.795; α = 105.49, β = 92.49, γ = 94.01 |
| Cell volume | 577.092 ų, Z = 2 |
| Axial ratios | 0.8754:1:1.5453calculated from COD 9014906 |
| Source structure | COD 9014906 (The Mineralogical Record, 2008) — 1 of 19 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.756 | 2.925 | 2.964 | 3.13 | 2.174 | 2.589 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 77.9 | 53.3 | 38.1 | 32.4 | 25.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9014906; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.666 g/cm³calculated from COD 9014906 |
|---|---|
| Hardness (Mohs) | 5.5-6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.4-3.68 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, brown, green, pink, red, rose, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | pearly, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 640.25 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ca 6.26%, Mn 34.32%, Si 21.93%, O 37.48% |
Classification
| Nickel-Strunz (10th) | 9.DK.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.DK.05Wikidata (CC0) |
| Dana (8th) | 65.4.1.1Wikidata (CC0) |