Aquamarine vs Topaz
Aquamarine and Topaz are genuine alternatives to one another — a choice somebody actually makes — and differ on 3 measured properties, crystal system most clearly.
Aquamarine vs Topaz
These are different kinds of thing (mineral variety, mineral). Fewer properties mean the same thing across both, so a like-for-like reading may not be available.
Aquamarine
Beryl coloured blue by iron — the same mineral as emerald, grown somewhere calmer, and usually clean because of it.
Topaz
Al2SiO4(F,OH)2
Mohs 8, and the reason there is a step between quartz and corundum — a hard silicate whose main significance is as a reference point and a gemstone.
| Property | Aquamarine | Topaz |
|---|---|---|
| Cleavage Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | perfect in one direction |
| Crystal system Categorical values can be listed side by side but not ordered or subtracted. | hexagonal | orthorhombic |
| Density | 2.66–2.8 g/cm³ | 3.49–3.57 g/cm³ higher |
| Lustre Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | vitreous |
| Mohs hardness Mohs hardness is an ordinal scale: values can be ranked, but differences and ratios between them are not meaningful. | 7.5–8 | 8 higher |
| Streak Only one of the two has a figure we can stand behind, so there is nothing to compare. | Not known | white |