Franklinite
ZnFe3+2O4IMA symbol: Frkgrandfathered
Franklinite is an oxide or hydroxide mineral with the formula ZnFe3+2O4, crystallizing in the cubic system. It has a Mohs hardness of 5.5-6.5, typically black in color, with a dull or metallic luster, a specific gravity of 5.07-5.22. Its streak is black or brown.
Photos
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Crystallography
| Crystal system | cubic crystal systemWikidata (CC0) |
|---|---|
| Space group | F d -3 m :1 |
| Cell (Å, °) | a = 8.443, b = 8.443, c = 8.443; α = 90, β = 90, γ = 90 |
| Cell volume | 601.853 ų, Z = 8 |
| Axial ratios | 1.0000:1:1.0000calculated from COD 9009894 |
| Source structure | COD 9009894 (Inorganic Chemistry, 2002) — 1 of 55 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 2.546 | 1.493 | 1.625 | 2.985 | 2.111 | 1.099 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 45.2 | 34.4 | 25.4 | 22.3 | 17.3 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9009894; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 5.338 g/cm³calculated from COD 9009894 |
|---|---|
| Hardness (Mohs) | 5.5-6.5single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 5.07-5.22 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | blacksingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | black, brown, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | dull, metallicsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Classification
| Nickel-Strunz (10th) | 4.BB.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 4.BB.05Wikidata (CC0) |
| Dana (8th) | 7.2.2.4Wikidata (CC0) |