Danburite
CaB2Si2O8IMA symbol: Dbugrandfathered
Danburite is a silicate mineral with the formula CaB2Si2O8, crystallizing in the orthorhombic system. It has a Mohs hardness of 7-7.25, typically colorless, white, brown or yellow in color, with a greasy or vitreous luster, a specific gravity of 2.97-3.02. Its streak is white.
Photos
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P n a m |
| Cell (Å, °) | a = 8.037, b = 8.757, c = 7.7218; α = 90, β = 90, γ = 90 |
| Cell volume | 543.46 ų, Z = 4 |
| Axial ratios | 0.9178:1:0.8818calculated from COD 9011472 |
| Source structure | COD 9011472 (Zeitschrift fur Kristallographie, 1985) — 1 of 8 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.565 | 2.961 | 3.442 | 3.234 | 2.653 | 2.744 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 89 | 81.3 | 71.3 | 65.1 | 60.7 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9011472; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 3.005 g/cm³calculated from COD 9011472 |
|---|---|
| Hardness (Mohs) | 7-7.25single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.97-3.02 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | brown, colorless, white, yellowsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | greasy, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 245.87 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ca 16.3%, B 8.79%, Si 22.85%, O 52.06% |
Classification
| Nickel-Strunz (10th) | 9.FA.65Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 9.FA.65Wikidata (CC0) |
| Dana (8th) | 56.3.1.1Wikidata (CC0) |