Nepheline
Na3K(Al4Si4O16)IMA symbol: Nphredefined
Nepheline is a silicate mineral with the formula Na3K(Al4Si4O16). It has a Mohs hardness of 5-6, typically black or red in color, with a vitreous luster, a specific gravity of 3.234. Its streak is brown; cleavage is none.
Photos
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Crystallography
| Space group | P 63 |
|---|---|
| Cell (Å, °) | a = 9.9762, b = 9.9762, c = 8.34957; α = 90, β = 90, γ = 120 |
| Cell volume | 719.66 ų, Z = 2 |
| Axial ratios | 1.0000:1:0.8369calculated from COD 4002835 |
| Source structure | COD 4002835 (Chemistry of Materials, 2017) — 1 of 33 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.002 | 3.837 | 3.265 | 4.175 | 2.34 | 2.88 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 94.5 | 77.8 | 65.2 | 53 | 43.6 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 4002835; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.568 g/cm³calculated from COD 4002835 |
|---|---|
| Hardness (Mohs) | 5-6single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 3.234 g/cm3single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Color | black, redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) brownsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Cleavage | nonesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 584.33 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Na 11.8%, K 6.69%, Al 18.47%, Si 19.23%, O 43.81% |
Classification
| Nickel-Strunz (10th) | 9.FA.05Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.FA.05Wikidata (CC0) |