Aragonite
Ca(CO3)IMA symbol: Arggrandfathered
Aragonite is a carbonate or nitrate mineral with the formula Ca(CO3), crystallizing in the orthorhombic system. It has a Mohs hardness of 3.5-4, typically white, red or violet in color, with a resinous or vitreous luster, a specific gravity of 2.93-2.95. Its streak is red.
Photos
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Crystallography
| Crystal system | orthorhombic crystal systemWikidata (CC0) |
|---|---|
| Space group | P m c n |
| Cell (Å, °) | a = 4.9667, b = 7.9775, c = 5.768; α = 90, β = 90, γ = 90 |
| Cell volume | 228.539 ų, Z = 4 |
| Axial ratios | 0.6226:1:0.7230calculated from COD 9014618 |
| Source structure | COD 9014618 (American Mineralogist, 2012) — 1 of 38 structures |
Powder X-ray diffraction (calculated)
| d (Å) | 3.404 | 1.98 | 3.281 | 2.712 | 2.38 | 1.749 |
|---|---|---|---|---|---|---|
| I/I₀ | 100 | 77.1 | 58.6 | 53.7 | 44.7 | 34.9 |
xrd-v1: CuKa1 1.5406A, 2theta 5-90, top10, Imax=100, no DW/PO. Computed from COD 9014618; idealized occupancies, no preferred orientation.
Physical properties
| Density (calculated) | 2.913 g/cm³calculated from COD 9014618 |
|---|---|
| Hardness (Mohs) | 3.75single sourceWikidata (CC0) 3.5-4single sourceDana, System of Mineralogy, 6th ed. (1892) |
| Specific gravity | 2.93-2.95 g/cm3corroboratedDana, System of Mineralogy, 6th ed. (1892) |
| Color | red, violet, whitesingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Streak | whitesingle sourceWikidata (CC0) redsingle sourceDana, System of Mineralogy, 6th ed. (1892) |
| Luster | resinous, vitreoussingle sourceDana, System of Mineralogy, 6th ed. (1892) |
Chemistry (calculated)
| Molecular weight | 100.09 g/molcalculated from the IMA formula |
|---|---|
| Composition (wt%) | Ca 40.04%, C 12%, O 47.96% |
Classification
| Nickel-Strunz (10th) | 5.AB.15Wikidata (CC0) |
|---|---|
| Nickel-Strunz (9th) | 5.AB.15Wikidata (CC0) |